PFLUGERVILLE, Texas — The mother of a man who lived with suspected serial bomber Mark Conditt in a home north of Austin says her son was kept in police custody until after Conditt died in a fatal confrontation with officers.

Jennifer Withers told The Associated Press that her 26-year-old son, Collin Thomas, was walking from work Tuesday night in Pflugerville to the house he and another man shared with Conditt when a group of officers “flew at him.” Withers, who spoke during an interview Thursday, said Thomas, was handcuffed, taken into custody by SWAT officers and questioned about the bombings.

She said he was held overnight but that none of his family was notified about where he was.

Conditt died early Wednesday after detonating a bomb as police were about to arrest him. Thomas was eventually released.

Police said earlier Thursday that they’d released Conditt’s other roommate. They refused to name him, saying he wasn’t currently under arrest.

Austin police spokeswoman Anna Sabana said neither roommate has been charged. She said she did not know why Thomas was detained forcibly in the way his mother described.

Withers said Thomas lived with Conditt for more than three months in a home Conditt was renovating with his father. She said her son was close to a family at the Christian church he attended, and that they introduced him to Conditt’s family who were also Christian.

She said her son and the 23-year-old Conditt, “seemed to get along fine.”

“Collin said they all would sit around and chat and talk,” Withers said.

She said her son didn’t know anything about the bombs and that she never got to meet Conditt.

Conditt’s first two bombs killed and injured black victims, leading to speculation that they were hate crimes — though investigators backed off those theories somewhat when subsequent victims were Hispanic and white.

They now say they don’t know what motivated him.

Conditt made a 25-minute cellphone recording before his death. It was recovered after he detonated one of his own bombs along the side of Interstate 35 just outside of Austin as a SWAT team moved in.

But investigators say the recording provides few clues as to Conditt’s motives — and they’ve refused to release it publicly, citing the ongoing investigation.

Conditt built bombs planted in different parts of Austin that killed two people and severely wounded four others over three weeks starting on March 2. He began by placing explosives in packages left overnight on doorsteps, then rigged an explosive to a tripwire along a public trail. Finally, he sent two parcels with bombs via FedEx.

As fear grew, Conditt eventually was tracked down through store surveillance video, cellphone signals and witness accounts of a customer shipping FedEx packages in a disguise that included a blond wig and gloves.

Police found him early Wednesday at a hotel. And when his car moved, they followed and forced him off the road, setting up the confrontation that ended in an explosion.

Austin Mayor Steve Adler praised police officers for stopping Conditt’s sport utility vehicle before he could get onto the highway, even though they were aware he likely had explosive devices inside and they did not have as much backup as planned.

“We hear about folks who run into danger to keep us safe and we had one of those moments in very graphic and specific detail,” Adler said at a news conference Thursday.

NAACP Austin President Nelson Linder said the manhunt’s end was a relief but that the public needs answers on what motivated Conditt, including whether the first two victims were targeted because they are from prominent black families.

“I don’t think it’s random at this point,” Linder said. “We’re going to withhold our judgment and keep searching for information and why he killed those people.”

Investigators have released few details about Conditt, who was unemployed, home-schooled and attended Austin Community College until 2012 but didn’t graduate.

The Austin American-Statesman reported Thursday that a bomb Conditt made and shipped via FedEx had been addressed to an employee at a downtown Austin spa. It was intercepted at a processing center without exploding.

Anita Ward works at Austin Med Spa and says that police and federal agents told her that her daughter, who also works there, was meant to be the recipient of the unexploded package.

Ward declined to name her daughter, who she said doesn’t know Conditt. Police haven’t commented.

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