This is the special report. From ABC news now. -- -- when I'm down Cutler in New York a new chapter in the war on terror a top al-Qaeda member stands before a federal judge. -- -- Laden's son in law... See More
This is the special report. From ABC news now. -- -- when I'm down Cutler in New York a new chapter in the war on terror a top al-Qaeda member stands before a federal judge. -- -- Laden's son in law pleaded not guilty in a New York City courtroom facing charges of conspiring to kill Americans. As a member of al-Qaeda. ABC's -- -- Bradley has the story. One of Al qaeda's most senior leaders Osama bin Laden's son in law appeared in New York federal court today to face terror charges sue -- Abu -- pleaded not guilty to a charge to conspire to kill Americans. In this video Abu Ghaith who served as al-Qaeda spokesman celebrates the 9/11 attacks on the US. Abu Ghaith was captured in January and brought to New York City last week according to US officials the CIA tracked his movement for years from Afghanistan to Iran. Then to Turkey where he was arrested once he left to Ronnie and territory. And got in the Turkey with very close monitoring by US government agencies. He was his days were numbered. Abu Ghaith was transfer to Jordan where the US picked them up. Officials tell ABC news -- gates has revealed key intelligence about al-Qaeda operations including its current status personnel and finances this is a man who's in the inner circle. The bin Laden's al-Qaeda operations. And now we have him alive. And he's talking. This is one of the first prosecutions of a senior al-Qaeda leader on US soil President Obama shortly after taking office pledged to try terror suspects in federal court. Some lawmakers would prefer -- -- face a military tribunal at one time. That will come that divide us -- putting people like this. Into federal court. Giving them the same constitutional rights is an American citizen. The Obama administration says that national security officials unanimously agreed to prosecute Abu gate. In civilian court believing it was in the best interest of US security. -- Bradley ABC news Washington. ABC's Eric -- he was inside the courtroom during that arraignment and he joins us now. Live with more -- and I want to know what was the scene like inside that courtroom. I think the most dramatic was just the scene itself to end because. The federal courthouse in lower Manhattan is mere blocks from the site of the 9/11 attacks that. -- who -- publicly -- that's the crux of the prosecution's case. They've charged him with conspiracy to kill Americans and their citing as evidence mainly his videos and audio recordings that he made. Immediately following the 9/11 attacks where he publicly praises the al-Qaeda agenda. He isn't charged in the attacks themselves -- -- any one particular plot. But it's that propaganda machine that he was behind prosecutors say that made it possible for al-Qaeda to recruit others to the cause. -- -- I want to ask you a little bit more about what the prosecution's case will be in going forward but first all right just a kind of set the -- -- what was his demeanor like as he was standing before the federal judge -- this is clearly a beaten man he walked in in handcuffs. It -- his hands shackled behind his back he had a blue prison smock. Bearded balding man -- short beard. And he simply sat there answered yes or no and Arabic to some basic questions but left it to his attorney a court appointed attorney. And Philip Weinstein who is going to be handling his case. And it was left to the court appointed attorney to say not guilty when the judge asked -- -- -- -- that charge of conspiring to kill US citizens looking at his face and his body. Movement didn't seem to understand exactly what was happening around him -- get. Going through a translator. -- it seems so so hard to tell we were sitting behind him in and you could sort of see. The bald spot in his head gleaming off -- strong courtroom lighting but. He appeared to to understand what was going on against him but remember. He arrived here in New York the first of march so he's been meeting -- attorney over the last couple of days. So I think he had a little bit of ground work laid forum about what he's going to be facing that effectively is life in prison. Assuming that he's found guilty a trial. So based on -- prosecution's case they're saying that a lot of their material is based on this 22 page statement. That he provided upon his arrest. The judge read some of those statements. What of those being a great army. Is gathering against Americans and how quote the storm shall not stop -- -- airplanes storm. When that signal was red up that he had a visible reaction to that. No visible reaction but these were statements that he made back in 2001 right after the 9/11 attacks and he was seen on video. Sitting right next to his father in law he had married Osama bin Laden's daughter -- -- -- one of his many daughters. And he was their right at his side sort of a warmup act for Osama bin Laden and that I'm and also Austria. Al qaeda's number two. And he was seen on that video doing exactly what the FBI is said Tuesday he's guilty of and that is being the mouthpiece the chief spokesman for. Al-Qaeda the statements that he gave over 22 pages to US law enforcement officials once he was in custody are gleaned from different interviews that he did. -- this sort of law enforcement officials it's not immediately clear whether those statements were made overseas where he was caught or whether they were made here in New York. Once he was so once he was brought here. Sometimes he was interrogated for his an intimate understanding of what may be in the works immediately. Otherwise we're told he was read his Miranda rights so those statements would likely come -- -- trial. As we heard in two months piece just a little bit earlier not everyone including some senior lawmakers are happy with the fact that -- terror suspect is being tried in a federal court. And as you have pointed out as well being so close to the site of the 9/11 attacks. What was the scene outside of the courtroom work are outside -- the courthouse in general where their protest whether it was or any when shouting with a difficult to get inside. No protests no shouting just a little bit of snow on the snowy day here in New York City and in fact there was no tighter security outside the courtroom the normal inside. Although gates was led in by two burly marshals in suits and their work about a dozen -- standing guard inside the courtroom but they're guarding mainly reporters. Court employees securities members of the FBI. It did not attract a big crowd. And in fact there are a number of other terrorist suspects on trial right now here in New York who had been extradited from overseas. And nobody really had said a word about them. This is an offshoot of Khalid Sheikh Mohammed in the Obama administration's decision to try Khalid Sheikh Mohammed another 9/11 conspirators here in New York. Eventually be administration relented. But some of the same people here in New York who objected to putting KSM on trial here said in this particular case for Osama bin Laden's son in law. It's not the same thing in and they've really had no problem with his trial going on here. What about his defense are they appealing his -- -- custody. No none of the moment -- there was no bail offered -- requested and the judge ordered him detained pending his next court date April 8. And the judge Lewis Kaplan is a fairly no nonsense guy he's likely to ask. At that April 8 conference for a trial date and prosecutors said they expect the trial would last about three weeks -- on the broader picture things how big of a victory is his capture in the war on terror you know we've heard from one of former counterterrorism official who who said then that this is not a small fish and here's why. Abu -- is one of maybe ten remaining core al-Qaeda members part of the -- original core al-Qaeda with Osama bin Laden. That still alive many have been captured many have been killed in drone strikes but there's only a few left. That this official told us could get the band back together he had that they -- the resources. Remember he was caught in Turkey -- a luxury hotel so he was thought to have access to the financing. And the people -- if he wanted to he could have gotten a -- back together that would have been interested in furthering -- cut emissions. And so authorities have been tracking his movements for the better part of a decade. He was in Afghanistan its spot as late as 2002. Then moved into Iran where he lived for the better part of the last decade before he finally was caught in Turkey. And so -- -- is over for today what is next for the case he'll be back in court on April 8 -- in the meantime prosecutors are going to have to give his court appointed attorney. All the evidence they have at least -- unclassified part if there's any classified material that comes into it -- than that there's going to have to be some separate movements there. But but once that materials turned over and and they come back before the judge next month. Then it's going to be a trial date and as I say prosecutors expect about three weeks. You're going to hear a lot of audio and video recordings during that trial a lot of statements. And -- -- has apparently already made to law enforcement officials that's the crux of the case right now. All right ABC's Eric deters -- covering the arraignment of Osama bin Laden's son in law in a federal court in lower Manhattan -- thank you for your time. And you reporting this afternoon again as we've been reporting Osama bin Laden's son a lot charged with conspiring to kill Americans a story that we will have a complete recap on abcnews.com. And of course the later updates right here on ABC news now for now. We -- return you back to your regularly scheduled program. So it's been a special group. From in the ABC news now.
This transcript has been automatically generated and may not be 100% accurate.