Transcript for Investigators on the hunt for serial bomber terrorizing Austin, Texas
Tonight the city of Austin on edge after the latest of three-week long wave of bombings in the region. I was on my back porch and heard the zblablast. Killing two and injuring five more. The bomber still at large with no suspect name. Typically people who do these type of bombs through the mail et cetera tend to be loaners, tend to be isolated, tend to be very angry. A guy thatlies alone or with a parent or on a basement of a house or on a farm outside Austin, all of the above are possible. Tonight authorities and first responders on high alert after an old military ordinance accidentally went off at a good will in the city. This incident is not related to any of the other incidents we've had here in Austin. We want to reiterate to the community if you see something suspicious, if you have a suspicious box, suspicious package, that you continue to call 911. The latest attack early Tuesday morning, a postal worker injured when a package bomb exploded at this FedEx if distribution center an hour outside of Austin. Authorities telling ABC news another explosive device has been found undebtonated in Austin wherethis morning's bomb was shipped from. Unexploded bomb are extremely helpful, you know how he built it, what materials he used, get DNA, hairs and fibers, trace evidence, finger prints of the bomb. It's the latest shaking attacks in Austin in five attacks in three wikileakss. Weeks. At Anthony house was killed after picking up a package dropped at his front door. And another deadly blast from a planted package. 17-year-old mason was killed his mother critically injured. We have trauma activation. Trauma, head and torso. His neighbors horrified. I saw ambulance with my neighbor on the stretcher, so that was very terrifying for me. Three miles away, another explosion just few hours later. Another planted bomb critically injured a 75-year-old woman, erpz Herrera. All of a sudden we heard skploegts a explosion and felt it move the ground. Police evacuated the area and alerted everyone not to tuck suspicious packages. We have a pattern in this community in the past ten days we believe are related. Authorities issuing a warning to residents. If you have a delivery that did not come through official mail service but instead you just found this item on your porch or in your yard and was unexpected do not touch it or move it, instead call us. Six days later miles away, a fourth wombombing rigged to a trip wire, two unsuspected bicyclists were injured. Residents are afraid to walk the streets. We went for a walk yesterday instead of me pushing her forward I pulled her behind me I'd rather it hit me than my baby. Than just 24 hours ago that fifth bombing in a FedEx facility. There's something significant about Austin to the bomber. My guess is he has a history there. He probably lives there or lives close by. He's mad about something. Once he's caught we'll figure it out. Authorities scrambling to make a connection and establish a motive. The first four victims of those three attacks all people of color but two victims on bikes were white. The first three appeared to be targeting a specific resident address, and whether they were targeting the person at that address or not we know they were placed on a specific doorstep at a specific home. Investigators chasing down hundreds of leads, more than a thousand suspicious package calls from frightened residents. Austin's police chief making an appeal to the public for any leads. We need every piece of informati information. Decades it was a tip from the public that solved another serial bomber case, the infamous unibomber. The FBI says it cannot find a pattern and admits the long investigation has been frustrating. In 1990s he was most wanted man in America. Cold-blooded bomber who alluded the FBI for 18 years. A ghost targeting universities and airlines. Killed three and injured more than 23. The FBI didn't have much information to go on. Then the uni-bomber gave the FBI more to work with when he contacted 9d media. This to large extent about getting attention. He demand two national newspapers print a Manu script or else the killings would continue and in 1995 his 35,000 word manifesto has posted. It is blackmail the times and post exceeded. Were they justified in doing so? History might say yes. Linda Patrick recognizes ideas that her husband and family had received from brother Ted. I interviewed her in her first television interview 20/20 homicide. Secret life of a unibomber. When she said I think your brother is a unibomber, I said this is nothing to worry about I've never seen Ted violent. But their suspicions kept growing. They posted the first few pages of the manifesto on the screen in the library and Dave went with me and as he read the first page his jaw dropped. I thought I was going to read the first page and turn to Linda and say see I told you so but at a emotional level it sounded like my brother's voice. The family made the wrenching decision to contact the FBI. Thought about the families that were bombed. There was one in which the package arrived to the man's home and his little two-year-old daughter was there. She was almost in the room when he opened the package. Luckily she left. And his wife left. And then he died. And there were others. So I spent those days thinking about those people. That tip from Patrick would end up being the linchpin to lead to Ted kizski in 1996 at his trial he was diagnosed with a serious mental illness, paranoid schizophrenia. He exchanged for life in prize kbroon. He is still in prison behind bars serving life. For the residentials in and around Austin another night on edge.
This transcript has been automatically generated and may not be 100% accurate.