AUSTIN, TEXAS (NYTIMES) - One of the housemates of the man responsible for a series of bombings in Texas has become a "person of interest" in the investigation, and officials now have evidence that the explosive devices were constructed at the suburban home the bomber shared, a Texas congressman said on Monday (March 26).
Investigators have still not found a clear motive to explain why the suspected bomber, Mark Conditt, 23, made and delivered homemade explosives that killed two people and terrorised the Texas capital for nearly three weeks before Conditt killed himself early on Wednesday morning.
Conditt was living in Pflugerville, the suburb north of Austin where he grew up. He shared a house there with two other men in their 20s. Both were initially detained by officials, questioned and then released.
Investigators have continued to question one of the housemates, who is now a person of interest in the case, Representative Michael McCaul, a Texas Republican, told Fox News on Monday.
Mr McCaul, chairman of the House Homeland Security Committee and a former federal prosecutor, said all seven of Conditt's explosive devices were built at the Pflugerville house.
"He did construct these bombs in the home," Mr McCaul said. "We know that much. They had to bring a robot in to dismantle and take out bomb-making materials. And the question is, did the roommate know that he was making these bombs at the time, for the last month, when all these bombings were still taking place?"
Officials have not released the names of either housemate, and Mr McCaul did not specify which one was the person of interest.
One was detained for hours before being released; the other was held longer, for one or two nights. Neither has been named as a suspect in the case. Mr McCaul said he did not know what, if anything, the housemate of interest had told police about his knowledge of Conditt's activities.
The Austin police's interim chief Brian Manley had previously declined to say whether the roommates were persons of interest.
"That's part of the ongoing investigation," he said on Saturday. "I know there are individuals, witnesses that we are speaking to. Whether there will be charges at some point in the future has yet to be determined."
Law enforcement officials have said they found evidence of Conditt's potential future targets, a mix of addresses and other locations that appeared to have no common thread to link them.
Investigators were continuing on Monday to sort through his computer hard drives and other evidence.
Before Conditt died, a federal criminal complaint was filed against him, charging him with unlawful possession and transfer of a destructive device, and a warrant was issued for his arrest.
A federal magistrate judge in Austin sealed an affidavit by investigators that would be expected to summarise their reasons for charging Conditt. It was unclear when that affidavit would be unsealed.
Investigators have said that Conditt used his cellphone to record a video while he was in his vehicle after a confrontation with the police in Round Rock, a suburb near Pflugerville.
Shorty after making the video, he detonated one of his bombs inside the vehicle, killing himself. The cellphone survived the explosion.
Mr McCaul, whose district includes parts of Austin and Pflugerville, apparently has seen the video. He described it on Fox News as a visually dark 25-minute confession.
"He said, 'I wish I was sorry, but I'm not,'" Mr McCaul said. "He refers to himself as a psychopath. 'I've been a sociopath all my life.' And then even more chilling at the end, he says that 'maybe I should just blow myself up at a McDonald's and end the whole thing.' That's where he was headed."
Officials said Conditt placed four fairly sophisticated homemade bombs in Austin, hidden in packages left on doorsteps or, in one case, placed with a tripwire along a sidewalk, concealed with a children-at-play sign.
In total, one of the worst serial bombers in America in decades killed two men; wounded four other people, including a 75-year-old woman; and terrified residents in the Austin and San Antonio regions.
During the height of the bombings, Austin police responded to 420 suspicious-package calls in one 24-hour period, all of them turning out to be false alarms.
Hundreds of local, state and federal agents and officers were hunting the serial bomber for days.
The state deployed a Pilatus high-altitude surveillance airplane that is more often used for border security and is equipped with a thermal imaging system.
Conditt was tracked to a hotel parking lot in Round Rock, and when he drove away in his red Nissan Pathfinder, the police followed him and confronted him; the chase ended in a ditch off Interstate 35, where one Austin SWAT officer fired his weapon and Conditt set off his bomb.
A justice of the peace in Williamson County, Mr Dain Johnson, said on Monday that Conditt died by his own hand.
"There is no final report yet, but the cause of death is suicide," Mr Johnson said. "He had multiple shrapnel injuries from the bomb."