[Tapper:] Welcome back to THE LEAD. We going to turn now to our national lead, the terrorist threat here at home. We are learning more details about one Ohio man's alleged plan to bomb Congress and then gun down lawmakers, and staff, and tourists as they fled. That's at least what a criminal complaint says this man, Christopher Lee Cornell, all of 20 years old, plotted to do. He even bought the guns he intended to mow down the lawmakers with, two M-15 rifles, and 600 bullets. The complaint alleges Cornell wanted to do all of this in the name of jihad under the name Raheel Mahrus Ubaydah. Luckily, his partner in this plot, someone that he thought was another would-be jihadist with whom he conspired online and over Twitter, that partner turned out to be an FBI informant. Yesterday, more than a dozen agents and local police broke down Ubaydah's door and took him into custody. Today the speaker of the house, John Boehner, who may have been among those in the cross-hairs, credited the FISA program, which allows for NSA snooping on communications, with preventing this attack. CNN's Alexandra Field is live for us in Cincinnati. Alex, you spoke to this man's father. What did he have to say about his son being accused of this horrific terrorist plot to systematically murder members of Congress, staff and tourists?
[Alexandra Field, Cnn Correspondent:] Hey, Jake. Both of his parents are heartbroken, devastated, as you would imagine they would be, but his father says to me that his son is 20 going on 16. This is a young man who lived with his parents, was working a seasonal job. The dad says that his son didn't have a car, rarely left the house, never left Cincinnati. The family thinks that he did not have the resources or the capability to pull off an attack, so what was he doing here buying guns? Well, the dad says he believes his son was coerced.
[Field:] John Cornell and Angel Carmen in their living room, shocked with the realization that their son is in custody, arrested in a sting operation and charged with plotting to blow up the U.S. Capitol.
[John Cornell, Father Of Capitol Terror Suspect:] Chris has never been out of Cincinnati. I believe he was coerced into a lot of this stuff. I believe that this so-called snitch filled his head with a lot of stuff.
[Field:] John Cornell says that his son recently took up an interest in Islam but emphasized its peaceful qualities and never mentioned is.
[Cornell:] My son is not a monster. I'm not just saying that because he's my son. If I thought he was up to something, I would have beat his butt and I would have been the first one to turn him in.
[Field:] The 20-year-old was first brought to the FBI's attention several months ago after social media posts talking about violent jihad. They say Cornell planned to detonate pipe bombs around the Capitol and then shoot people as they fled. But a man Cornell believed would be his partner in the plot was actually an FBI informant. The FBI says Cornell told the informant he had contacts overseas, that he had aligned himself with ISIS and believed lawmakers were his enemy. The criminal complaint says Cornell did not think he would receive ISIS authorization to conduct a terrorist attack in the United States, but he wanted to wage jihad on his own, writing, "I believe we should meet up and make our own group in alliance with the Islamic State here and plan operations ourselves." According to investigators, he researched the targeted government buildings and the construction of pipe bombs. Wednesday, Cornell purchased two AR-15s and 600 rounds of ammunition from this gun store in Cincinnati before FBI agents arrested him in the parking lot. The gun store owner, who was working with authorities, described Cornell's demeanor.
[John Dean, Point Blank Gun Store Owner:] Well-spoken but soft-spoken. Lots of questions. He's a little chatty. If I hadn't had been given any kind of warning ahead of time, I probably would not have suspected him as up to what he was doing.
[Field:] CNN has repeatedly reached out to Cornell's court appointed attorney, but has not received any response. Cornell's bedroom, which he shared with his brother, seemingly that of a typical young man with movie posters and video games. The principal at the high school he attended and where he wrestled described Cornell to CNN as a normal student, saying, "Christopher was not a disruption or a discipline problem in school. A quiet, but not overly reserved student who would participate in class, did not withdraw from his class work." But now, authorities are tracing the steps of the young man accused of a plot to attack his own country. Because investigators were following Cornell, they say law makers were never in imminent danger and, Jake, Cornell will appear in court tomorrow.
[Tapper:] Alexandra Field in Cincinnati, thanks so much for that report. That's it for THE LEAD. I'm Jake Tapper. I now turn you over to Wolf Blitzer in THE SITUATION ROOM. Wolf?