AUSTIN (KXAN) — Six months after Mark Conditt terrorized Austin with a series of deadly homemade bombs, one of his roommates is sharing his perspective of the experience for the first time.

Collin Thomas, 26, was one of the closest people to the Austin serial bomber. Leading up to and during the bombings, he says the two lived together for six months in a small Pflugerville home owned by Conditt’s parents. Thomas rented the space along with another roommate.

Hours before police were closing in on Conditt’s vehicle, the Federal Bureau of Investigation was trying to figure out if Thomas and the third roommate were involved or had any prior knowledge of the execution of the bombings. Thomas took KXAN’s Erin Cargile back to the neighborhood street where he was walking when FBI detectives stopped him and held him at gunpoint.

“They handcuffed me like that,” Thomas said putting his hands together. “And I was sitting down like this and then they took my phone away.”

Following a 2-hour interrogation, Thomas says authorities held him for another 10 hours at Austin Police headquarters. 

“They kept asking me about my roommate multiple times and I kept thinking, ‘It’s gotta be a mistake,'” Thomas said.

Bombings plotted in the room next door

Thomas says they met through mutual friends before moving in together, and Conditt seemed completely normal.

“He was the type of person to want to take the shirt off his back and help you out,” Thomas said.

His roommate was helpful, but also extremely private. Thomas says Conditt never let anyone in his bedroom, and always kept the door locked except for one time when Thomas was moving in.

“He liked to tinker with a lot of computers,” said Thomas. “He told me he built his own server so I see all these wires going through his room and I say ‘Oh, that’s pretty cool.'”

Thomas says he learned about the bombings like everyone else, via news outlets, and keeps thinking back to a conversation he says Conditt initiated in their living room. Thomas says he walked in on Conditt and their other roommate talking about the bombings.

“It was scary and my roommate asked me, ‘Are you not afraid?’ And this is what I think might’ve saved our lives. Mark, the bomber, looked at me and I said, ‘No, I’m not afraid because you can’t let the bad guys win because that’s what they want,'” said Thomas.

During the course of the conversation, Thomas says Conditt accused him of being the bomber, and was clearly looking for a reaction. He also says their rooms were about three feet away from each other and believes Conditt was making the bombs in his bedroom.

“I don’t think he would’ve done it anywhere else,” said Thomas. “And that’s what scares me after the fact — that I could’ve died. One little mistake and boom it would’ve all been over.”

The question Thomas hears the most: How did he not know what was going on in the room next door?

“I’m sorry guys, I’m a human being. I don’t know everything that my next-door neighbor is doing,” Thomas said.

Since finding out his roommate was the serial bomber, Thomas says he has struggled with post-traumatic stress disorder and depression and is still full of anger.

“The fact that he can sit and smile knowing that he killed people, the fact that he can pretend, you know, be a friend when he’s really doing what he was doing in his room the entire time — that’s what I’m angry about.”

Thomas is in the process of writing a memoir called “Sleeping Next to Death.” The book is set to be released in January 2019 and is another step in the healing process.

“I’m glad he’s dead, let’s be honest, people like that don’t need to be living in this world. You can’t let them win.”

A look at the lives forever changed by the Austin bomber

Anthony Stephan House, 39. The first person to pick up a bomb disguised as a package left at his front door. It exploded when he picked it up, and he did not survive the blast.

Draylen Mason, 17, and his mom. They brought a bomb disguised as a package inside their home. It exploded in the kitchen. Draylen did not survive, and his mother was injured.

Esperanza Morena Herrera, 75. She was injured after a package outside her home exploded when she picked it up.

William Grote, III, 22, and Colton Mathes, 23. Grote was riding his bike on the street and his friend was walking on the sidewalk when they triggered a bomb. The device was attached to a tripwire, which was different than the three previous package bombs.

Why is the Austin bomber case not closed?

Austin police tell KXAN the FBI continues to investigate the case. Detectives still have a limited number of interviews to conduct and are still evaluating DNA evidence along with phone and computer records.

Earlier this month, a Williamson County grand jury heard evidence surrounding the final takedown of Mark Conditt. Jurors cleared the Austin police officer who fired a weapon during the attempted arrest. 

Austin Police Chief Brian Manley says he is still trying to decide if the department will release a 25-minute recording from the bomber where he confesses to the crimes and explains mistakes he made that allowed law enforcement to track him down.

Manley fears it could do more harm than good, and better educate someone who might consider carrying out a similar crime in the future.

Exclusive extended interview with the Austin bomber’s roommate, Collin Thomas: