Transcript for Police Say Alleged South Pasadena School Shooting Plot Was 'Viable'
We're all kind of scared inside the announce that it should say OK let's just hope this doesn't happen again. Students stunned and one California high school where police say they foiled a deadly plot potential mass shooting. Classes at that school in South Pasadena cancel today's stories are trying to sort this all out. -- when I'm down Cutler in New York to students. Are in custody today that school those students -- relieved that this alleged plot did not see the light Tuesday. It's a very safe school. So I can I just can't imagine anything I think actually going on this is -- Syria so there really that could happen. Authorities in Los Angeles about talk about the investigation and at a news conference about to begin in just few moments we will take you there but first. I want to bring in ABC's Alex Stone who's standing by at a Los Angeles bureau to talk about this Alex first tell me about this plot what do we know was plant. But we do expect to find out more here in just a second win that police in South Pasadena -- -- stand and -- right now not a whole lot is known except that they believe this was a credible threat of some kind but. It does not appear at this point we may find out differently here and a couple of minutes they actually had any weapons but somehow. This school became. Aware of what ways allegedly being planned here. They notified police police -- -- went and carried out two search warrants earlier today. Apparently finding evidence according to place inside the homes of the two students -- They are now under arrest and we expect to find out here in just -- Bowman. How serious of a threat this actually wants do we have any ideas are waiting for -- information -- any idea exactly how police got tipped off to begin with. We don't know except that -- came from school officials and somehow the school became aware that something wise apparently in the works and then they contacted police to say. Hey look there is something here we don't know what it is you should check it sound and this was again and I'm saying apparently allegedly a lot because we don't know what at a time. But that this was this something that they were planning for the first couple of days of school which would have been later this week in South Pasadena -- Could have been the first day of school on Thursday. But within those first couple of days of classes resuming and again because it's still fluid situation and obviously police have released a very little information do we know -- much about those two students that are in custody. We don't know -- we don't know much about them all except that they're reportedly seniors who were just about to begin their at their senior years. And obviously with the school starting this is something that all schools are looking at an aware of right now that. That threat could resume remember at the end of the school year it seem like we had. -- daily cases of either threats or actual active shooters who were found over a couple of days on campus isn't in public areas. I itself we have to see now how serious this was -- -- -- -- go to that news conference where the police chief is actually at the Mike. The south pass any of -- department was notified. By the high school staff that they had received information of a possible threat to the school that shooting was -- occur there. Officers were dispatched to the school had received the information. And once they receive information they felt that it was viable enough to make a crime report on that. I met with detectives and officers that were investigating the case we -- a game plan to. Go forward with they -- full press investigation. We had detectives working on this case since last Thursday. Pretty much around the clock all the way through yesterday afternoon when we made an arrest of two subjects. What we learned was there was -- social media we had our detectives do some Internet surveillance. The subjects that that were arrested. And found that in in our opinion that it was very viable what they were plotting that they were making that. A huge. A huge plan. The school massacre. They had identified. Three staff members at the school by name that they were targeting. Along with some some random students as they called -- they just wanted to. As they put it they just wanted to kill as many people as possible. Very frightening experience. For the school and that's why we took it so seriously and continued on with the investigation. Through its through the arrest. On Saturday this last Saturday the detectives with the all the all the evidence that they had gleaned from their surveillance. They went to the tedious task of compiling the evidence. And then making make getting enough information so that they -- -- a search warrant for the for the residents. In this in this case. On Monday August 18. The detectives presented me. A search warrant request to a judge the judge reviewed the information and immediately signed the the search warrant. -- you felt that. The investigation. Determined that that threats were very very viable. Later that later that afternoon. Our detectives along with the patrol personnel. Went to two residents in two houses in South Pasadena. And -- the search warrants. And it was there that they discovered. Within they're taking the computers that's -- main. The main source of information that we have on this but it also it coincided with. Some of the information that we received from the suspects later on we did the interviews. So it all all the all the pieces fell together as far as that went. Later today the our detectives will present the the case -- the district attorney for filing consideration. And it'll be at that time that will be it will have more information for you as the day progresses. Because the wheels of justice do turns slowly sometimes and not on anyone's particular schedule. But we do have -- detectives specifically assigned in this case who will hand carry this -- that the to the DA's office. Later this afternoon. Both subjects were arrested for conspiracy and criminal threats. And it'll be determined later whether additional charges -- can't be filed. The FBI has reached out to us and we have taken up their offer -- will work with them. We've consulted with them and accorded a coordinated effort we will. Use their services to to do some forensics on the computers and also -- officer and some guidance they will offer some guidance. On how the investigation should proceed because there was some. There was some talked it within the within the chatter on the Internet. About. Making explosive devices bonds and whatnot. So. At this point I just want the the community and now. That this is something that we take very seriously and something that we're gonna address every single time. We're gonna do everything we can to keep our communities safe. We get we don't take threats lightly we will investigate -- -- and of course when we can we will bring people to the justice system. This particular. Thursday is the opening. Of our school year. And as is a tradition here we always provide extra patrol to our schools we have five schools in our city. -- this case I've asked for off duty officers to -- in. And work work around the schools -- conducting foot beats driving a patrol cars. And I want there to be a sense of of safety within our community and it's not I'm only doing this toward the fact that. I want people to feel very comfortable that they are being that they're being. -- properly -- secured. Last January as a side note. Our police department in conjunction with the school district started conducting a active shooter training and it was a process of three separate training events that was designed by our department. And in March we we did -- an active shooter training -- And while that was. Very. Labor intensive costs intensive. I think that the awareness that we received from that training both from the police department's perspective. And the school's perspective. I think that today. Really signifies that we may have saved some lives today -- -- I think we've really save lives. And I think that we have to remember that. This is an ongoing investigation we will be as forthright and thing and come forward as much information as we can. But -- tell the investigation. Continues it unfolds. That's all the information I have at this time. I will take questions at this time if you haven't. Well the three or four days worth of surveillance on the Internet indicated that. They had a very real threat they had a -- -- -- plan in mind that they were gonna execute. And later on during our investigative. Interviews with with the suspects that gave more -- less -- -- -- what they have talked about very cold hard cold heartedly in the in the investigation and interviews any -- what is. -- -- when you really. Turning his. Three. So the question is is how close -- -- -- have in resources -- where they had to actually making this come true. Like anything else everything has a beginning and this is at at the very beginning of their plot to to create this massacre. They're very steadfast in the conversation. During the during their chatter back and forth. And it was it was very very viable that was something that we don't want to take as as a as a hoax. -- what what I can tell what. But what I can tell you is this that there we have two male subjects that seventeen and sixteen years old and that's legally all that I can really tell you about that. Aside from it. There was no target date and there was. As they were as they were. Investigated I'm sorry as they were planning. They didn't have a target date but they had a very very specific plan how they're going to carry out there and there are. Six mission. I'm sorry. Right what they had talked about they had researched. Weaponry. How to make explosives. The how to disarm people. They we're researching that tactical elements on how to how do you go and indeed the aggressor with with -- firearms. The motive I can't discuss at this time it would be too early to take up to talk about that suffice to say that -- any motive would not to rise the level of the response that they had. -- Yes so with obviously a South Pasadena is very close -- -- community. The the school had learned from a community member that this plot was going on. And the school because we have such a close relationship they they called us immediately. They let that they let us go forward with with starting to investigated so I think the key here is that. Let let people in their specific. In their specific jobs let them do what they know how to do. There was a little bit of information that we took and we are able to. -- to glean more information as investigation continued. And it's it's it's really a collaboration between the community the schools and I asked. Already -- a live stream this news conference from South Pasadena, California where police -- there is briefing members of the media gone about. A foiled school supplies like just ahead of the opening of the school year for South Pasadena want to bring it out stone was in our LA bureau following the story in this. -- house asking some questions. We -- -- have a lot of information going into the special report on on the fact that we knew that there was some kind of a plot that had been foiled by police there in conjunction. With the school what did we find out -- from this news conference. The united still there's a lot it's not known it appears in this was in the very early planning stages potentially being explosives and firearms but. That they apparently didn't have the firearms they may not have had the explosives either. The chief they're not going into a lot of detail except saying it was a seventeen and a sixteen year old suspect suspects were two of them. But it just how close they were to actually carrying this out. Still isn't clear it sounds like they work well all that close except that they have a lot of mode of and they were saying now lot of stuff on social media. But I just how close they were hard to tell based on the chief to -- the F. BI now getting involved in this and police really -- a lot of there were no other investigation based on line each front online chatter. Which is why the -- -- they had confiscated computers from two residents. On Monday. The charges that are going to be presented this afternoon to the district attorney conspiracy and criminal threats again against that sixteen and seventeen year old involved in this. Tell me a little bit about South Pasadena how -- of a community is it. Well it's that close to Pasadena fairly small community and -- right on those charges notice there aren't any weapons charges there aren't any explosives charges in -- conspiracy and criminal threats that what they're going with here. The other you know interesting note is -- in Valencia north of LA about. Half an hour north of LA this week. A a teenager a student was arrested for threats against Valencia high school. -- very graphic threats on line on social media that one didn't get quite as much attention. But -- least. On the basics of the case sounds somewhat similar of somebody was making a lot of threats online may not have actually had the means to carry it out at least yet. Based on what police found in the home. But this one it seems police. May have thought was further along. In the one in Senecal Rita in Valencia that was uncovered two days ago what are the things that you've talked about -- news conference was also the training that his department had undergone earlier this year. About handling a situation if in fact it would've been carried out. He seemed to go at lengths about the added that the difficulty that the financial responsibility. And the task and the success that they have from that kind of training program. Well yeah you know since column -- in 1999 schools have prepared and they have practiced more so in recent years after so many school shootings that. Here in California. Growing up here you do duck and cover drills for earthquakes along with fire drills many schools are now doing active shooter -- drills as well that. This is something that now students are growing up with think kids are growing up with in case something. An actual active shooter. Happened on campus and in this case the chief there in South Pasadena saying. This is something that they are now drilling for the message also saying he said this I think we really saved lives based on. The response that the police department took from that early tip up on this. And schools still scheduled to start this Thursday correct. -- day after tomorrow and they don't know exactly win this was -- being planned for when these students wanted to carry it out there initially had been some talk. That this was being planned for opening day of classes on Thursday. At least from what the chief said there doesn't sound like they were ready to go by that time because. They were more in just the planning stages nonetheless it was very serious and they don't know what the time span was. How they did carry out the two search warrants at the homes of the -- members of their families. Now again one of the students apparently trying to get away from police when they arrived to -- acute that search warrant. That that they may have known why police were likely there but all of this coming from chatter online. Increase security will definitely be present this Thursday when school does beginning and as was noted there by the police chief. ABC's Alex Stone at our bureau in Los -- out thank you for that for -- the very latest on that story appreciate that. And of course you can keep up with the story in real time by downloading the ABC news -- and started a story for exclusive updates on the -- For now I'm down -- New York.
This transcript has been automatically generated and may not be 100% accurate.