Mark Conditt lamented his poor judgment in attempting to send two explosives through FedEx, a mistake he assumed had enabled investigators to identify him as the culprit. He was right.

AUSTIN, Texas — In the 28-minute confession he recorded on his phone shortly before his death, Austin serial bomber Mark Conditt lamented his poor judgment in attempting to send two explosives through FedEx, a mistake he assumed had enabled investigators to identify him as the culprit.

He was right.

After 20 days of churning through theories about the explosions and chasing down tips, the final 20 hours of the hunt for the bomber unfolded in a rapid stream of breakthroughs, starting with police on Tuesday morning identifying Conditt in surveillance video in and around the Sunset Valley FedEx and ending early Wednesday with him detonating a bomb in his car as officers surrounded him.

Conditt had already been on investigators' radar as one of several possible suspects. After plowing through stacks of retail receipts from hardware stores and big box retailers, they had learned about his purchases of nails and electronics that could be used in bombs. But they didn't know for certain that he was behind the attacks until they reviewed the FedEx surveillance video.

"The biggest clue or piece of evidence really was the suspect's fatal mistake: walking into the FedEx office," said U.S. Rep. Michael McCaul, R-Texas. "Up to that point, he had avoided surveillance cameras."

Led by the Austin Police Department, the team involved more than 500 officers and investigators from the FBI, the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives, the Texas Department of Public Safety and other agencies.

They employed such advanced technology as cellphone tracking and forensic analysis of bomb components. The DPS, for instance, supplied the team with one of its Pilatus spy planes, which were purchased to aid the state's border security campaign and can provide high-definition live video of targets on the ground from high altitudes. But they also relied heavily on old-fashioned police work, like scouring parking lots for Conditt's red Nissan Pathfinder.

There are still many unanswered questions about the frantic final hours of the chase for Conditt, but here's what we know so far about how the events unfolded.

After a package exploded early Tuesday in a FedEx distribution center in Schertz, investigators tracked it back to the FedEx retail store in Sunset Valley, reviewed the surveillance video and got a glimpse of Conditt wearing a blonde wig and baseball cap.

Video outside the store showed him getting in a red 2002 Ford Ranger, although they could not read the license plate, The New York Times reported. Witnesses of the previous bombings had reported seeing a red truck before the explosions, giving investigators hope that they were on the right path, McCaul said. Investigators then confirmed that the truck belonged to Conditt and made him the primary suspect.

Now that the authorities knew Conditt was behind the bombings, it was time to find him.

One reason Conditt had eluded authorities for so long is that he had been careful about not having his cellphone on at key moments during the bombings, McCaul said. His phone was off for much of Tuesday, making the search difficult, he said.

Unable to precisely locate him right away, investigators went about tracing him. They used a search warrant to get Google to turn over Conditt's recent internet search history, an official told The Austin American-Statesman on Wednesday. The data revealed that he had been searching for locations in Cedar Park, and police on Tuesday warned residents at those addresses that they may be targeted.

Although they still didn't know exactly where he was, officials prepared for a raid on Conditt's home in Pflugerville. During the preparations, a miscommunication led a two-man paramedic crew from the Pflugerville Fire Department to knock on Conditt's door, not knowing that he was connected to the bombings.

The plan had been for them to wait nearby and be on hand in case someone was injured during the raid.

One of Conditt's two roommates answered the door and said there was no emergency. It's possible the roommate told Conditt about the paramedics' visit. The mistake could have resulted in disaster for the investigation if Conditt had fled or committed more killings knowing that the end of his run was near.

Conditt recorded the 28-minute statement on his phone Tuesday night and indicated that he knew investigators were closing in, interim Austin Police Chief Brian Manley said. He also described the seven explosive devices he made, talked about personal struggles and said he had no remorse for his actions, according to police and sources familiar with the recording.

"I wish I were sorry but I am not," Conditt said in the video, according to the sources.

He also said that he planned to go to a crowded McDonald's and blow himself up if he felt he was about to be arrested.

Like his decision to attempt to deliver bombs through FedEx after at first dropping package bombs at victims' homes himself, Conditt's increasingly sloppy use of his phone later in his spree might have helped the police.

Officials learned that Conditt was in the Round Rock area around midnight, after he turned his phone on and caused it to "ping" a cell tower, McCaul said.

U.S. marshals then fanned out across Round Rock and checked out every hotel, motel or restaurant that was still open. They soon found what they were looking for in a hotel parking lot: a red Nissan Pathfinder, Conditt's other car.

After observing the vehicle for 15 to 20 minutes, they noticed exhaust coming from the tailpipe, signaling that it was occupied, and called for backup. "When you've been searching and you've been trying to turn up every stone that you can overturn, (when) you've been working this for hours and days at a time ... and you see that vehicle, you are excited," Deputy U.S. Marshal Brandon Filla said.

Twenty to 25 minutes later, before all of the team of officers arrived to arrest Conditt, he pulled out of the parking lot. The marshals followed Conditt and called for police to organize a "tactical stop" as he was heading toward Interstate 35.

The tactical stop forced Conditt to pull into a ditch along the highway shortly after 2 a.m. SWAT officers approached the vehicle with guns drawn. As they were reaching it, Conditt detonated a bomb, and one of the officers fired a shot into his car. The blast knocked some of the officers off their feet and injured one. And when the smoke cleared, Conditt was dead. (On Friday, Conditt's death was ruled a suicide caused by "multiple penetrating shrapnel injuries," said Dain Johnson, a Williamson County justice of the peace.)

The chase was over.