(CNN) -- The death of the Austin bomber brought some relief to the Texas capital. But as authorities dig through the evidence, even they acknowledge the motive is a mystery.
Mark Anthony Conditt recorded a 25-minute confession and killed himself in a final explosion, ending a wave of package bombings that terrorized Austin for weeks.
But none of the evidence that investigators have gathered has yet given police many clues as to what motivated the 23-year-old man to embark on a nearly month-long spree of violence.
"It is the outcry of a very challenged young man talking about challenges in his life that led him to this point," Austin police Chief Brian Manley said of the video.
"I know everybody is interested in a motive and understanding why. And we're never going to be able to put a (rationale) behind these acts."
A confession video
A 25-minute recording was found on Conditt's cellphone when police recovered his body Wednesday morning.
In his confession, Conditt described the components of seven bombs he built -- including, authorities believe, the one he used to kill himself -- and detailed the differences among the bombs, Manley said.
But the video itself failed to shed light on a possible motive. He did not make any references suggesting involvement with terror groups or that the bombings were hate crimes.
"I know everybody is interested in a motive and understanding why. And we're never going to be able to put a (rationale) behind these acts," Manley told reporters Wednesday night.
Inside the bombmaking lair
Federal agents searched for hours the home that Conditt shared with at least two people.
SWAT vans, robots and dozens of officers in tactical uniforms flooded the streets of Pflugerville, an Austin suburb of about 50,000 people.
Inside a room, agents found components for making similar bombs to the ones that exploded in the past weeks, said Fred Milanowski, the special agent in charge for the Bureau of Alcohol, Tobacco, Firearms and Explosives' Houston office.
Agents did not find any finished bombs on Wednesday, Milanowski said.
The devices that exploded in Austin and near San Antonio were pipe bombs with batteries and smokeless powder and were constructed with materials found in a hardware or sporting goods store, a law enforcement source with knowledge of the investigation told CNN
The bombs had distinctive shrapnel inside. Some had "mouse trap" switches and others had "clothespin" switches, the source said.
Frank Alvarado and his two children were among several people who were asked to evacuate homes and businesses within five blocks of Conditt's home as agents removed explosives.
"You would never think it's going to happen over here because everything was happening down south," Alvarado told CNN affiliate KXAN. "You never think it's this close to home -- I'm just two blocks away."
Pink gloves, receipts led police to suspect
Knowing that all the bombs were made from common household items, investigators went area stores scanning receipts and looking for suspicious purchases.
That led them to consider Conditt as a person of interest until surveillance footage from a FedEx store south of Austin captured a man in a baseball cap, blonde wig and pink gloves bringing two packages to the store.
"Police say that they used that as the final piece to put all of this together, really in the past 24 hours," Tony Plohetski, an investigative reporter for the Austin American-Statesman, told CNN's "New Day."
Investigators used cellphone technology Tuesday night to track Conditt to a hotel in Round Rock, about 20 miles north of Austin. There, they spotted his vehicle.
Police and federal agents surrounded the hotel but didn't move in immediately. They wanted to wait for backup because they were dealing with a suspected serial bomber.
They were still awaiting the arrival of those teams when, some time later, Conditt took off in his vehicle. Police followed him as he drove on the service road along I-35 until he stopped on the side of the road.
As a SWAT team cautiously approached, Conditt detonated a device inside his red SUV and died in the blast.
What his roommates knew
Conditt's two roommates were detained and questioned by police as investigators try to determine if he acted alone.
They were not arrested and neither roommate was identified.
Jennifer Whiters said her son moved to Conditt's three-bedroom home after a friend told him about a room for lease that was vacant.
In the three months that his son has lived at the Pflugerville home, Withers said she never saw Conditt and that her son didn't express any concerns.
"Nothing seemed out of the ordinary," she told KXAN. "We didn't suspect anything. He didn't suspect anything."
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