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The Texas bombing suspect's cellphone had a 25-minute video recording in which he described how he built each explosive device "with a level of specificity" that the Austin chief of police classified as "a confession" at a late Wednesday news conference.

The phone was found on the suspect after he died in an explosion early Wednesday as police closed in, Austin Police Chief Brian Manley said. In the recording, the suspect, Mark Anthony Conditt, described the bombs that he constructed to such a degree that he also explained how they differed, which is information that had not been released, Manley explained.

"He does not at all mention anything about terrorism or anything about hate," Manley said, who added that the video did not necessarily clarify a motive.

"Instead, it is the outcry of a very challenged young man talking about challenges in his personal life that led him to this point," he said.

Earlier on Wednesday, multiple senior law enforcement sources said that "exotic" batteries ordered online helped lead authorities to Conditt, as Austin police and federal agents worked around the clock with approximately 500 agents to track down the bombing suspect.

Mark Anthony Conditt Austin Community College

A criminal complaint filed before the suspect died identified him as Conditt, 23. (Police had said earlier that Conditt was 24.) Newly unsealed court records said Conditt would have been charged with receiving, possessing and transferring a destructive device.

Law enforcement remained at the scene around his home on Wednesday afternoon.

The unusual batteries were the signature trait that allowed investigators to quickly link the various explosives to Conditt, sources said. One senior law enforcement official said the batteries came from Asia.

"These weren't your store-bought Duracells," another law enforcement official said.

Related: Trail to Austin bombing suspect combined high-tech and old-fashioned techniques

Conditt, suspected in a spate of bombings that terrorized Austin in the last three weeks, died early Wednesday after detonating an explosive inside his vehicle as a SWAT team tried to apprehend him on the side of a highway, officials said.

Authorities had tracked him to a hotel in Round Rock, a city in the Austin metropolitan area, Manley said at a news conference.

When investigators examined Conditt's home in Pflugerville, Texas — just outside Austin — they found a "treasure trove" of evidence, multiple senior law enforcement officials said. That forced authorities to clear the six surrounding blocks due to a significant amount of bomb-making material.

Pflugerville Police Chief Jessica Robledo said at a news conference Wednesday that it would likely take several hours to process the scene and safely removed the explosive material, but added that authorities would allow residents to return home as soon as possible.

Fred Milanowski, ATF special agent in charge of the Houston field division, said that investigators believe there are no other devices in the public, but shared with reporters that they had found a "considerable amount" of bomb-making material in one of Conditt's rooms, which had "a lock on it."

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"There is componentry in there that makes us believe to a high degree of certainty that it’s the same componentry that they've found in other devices," he said.

Police were able to find Conditt using a variety of tactics, including coming up with a list of phone numbers and individuals that were in the area of the bombings when they occurred, using cell-site analysis and high-tech computing systems that can find patterns of callers in certain areas.

Hours before police tried to pull Conditt, he turned on his cellphone, which allowed authorities to track his location. Surveillance footage taken at an Austin FedEx was also used.

Authorities shared the surveillance footage showing a man believed to be Conditt entering a FedEx facility wearing what appeared to be a blonde wig and dropping off a package.

Early Wednesday, police were following Conditt's car on Interstate 35 when he pulled over and "detonated a bomb inside the vehicle, knocking one of our SWAT officers back," Manley said.

Another member of the SWAT team fired at the vehicle, Manley said.

"The suspect is deceased and has significant injuries from a blast that occurred from detonating a bomb inside his vehicle," he said, adding that the officer who was knocked back sustained minor injuries.

The incident happened at around 2 a.m. local time (3 a.m. ET), according to NBC affiliate KXAN.

Earlier on Wednesday, Rep. Mike McCaul, R-Texas, told KXAN that Conditt purchased some of the materials at a local Home Depot.

The components included galvanized steel pipe, an explosive and several different types of shrapnel, law enforcement officials briefed on the investigation said.

Some items were allegedly purchased online, and Conditt allegedly used the name "Kelly Killmore" on shipping, according to NBC News affiliate WOAI.

The completed devices were triggered via a rudimentary switch or pin system when the packages were opened or jostled, officials said. By opening or jostling the package, paper or some sort of wadding that was between the switch was removed, closing the circuit, and detonating the device.