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(CNN) —  

Austin bomber Mark Anthony Conditt used a “Drive Like Your Kids Live Here” yard sign to hide one of his homemade bombs, and all his devices contained shrapnel, according to an affidavit.

A federal judge on Monday unsealed the affidavit and dismissed a criminal complaint against Conditt, said John Bash, United States attorney for the Western District of Texas. Conditt killed himself hours after authorities filed the complaint on March 20. It charged him with one count of unlawful possession and transfer of a destructive device, Bash said.

“The defendant is dead. There’s not going to be a prosecution,” Bash told reporters Monday.

The affidavit revealed details about the construction of the bombs along with Conditt’s planning and preparation.

Officials said Conditt, 23, was responsible for making seven devices, killing two people and wounding five others in Austin and near San Antonio over nearly three weeks in March. He blew himself up with one of his bombs as police approached his vehicle.

Conditt recorded a video confessing to the crimes, interim Austin Police Chief Brian Manley said then. The confession did not shed light on a motive, Manley said.

Authorities are still investigating Conditt’s motive and intent, Bash said. There are no further suspects at this time and authorities do not believe there are any more destructive devices out there, Bash said.

In the days leading up to the incidents, Conditt bought items used in the bombings, the affidavit said.

On February 27, a customer using a credit card issued to Conditt bought battery holders with snap connectors from an Austin electronics store, according to the affidavit from a special agent with the Bureau of Alcohol, Tobacco, Firearms and Explosives.

The customer resembled Conditt in the video footage from the store, the affidavit said.

The six bombs used battery holders with snap connectors, according to the affidavit.

On March 13, a man bought several signs, including the “Drive Like Your Kids Live Here” sign, from a Home Depot in Round Rock, Texas, the affidavit said. The customer, who was also captured on a store surveillance video, looked like the man in a photograph the ATF agent had, the affidavit said.

A confidential source, who had multiple interactions with Conditt, identified him from the photograph, and confirmed that he and the man in the Home Depot surveillance video were the same person, the affidavit said.

Five days later, a witness who lived near one explosion in a residential area said a resident returned home to find the “Drive Like Your Kids Live Here” yard sign, with red backing and white letters. The sign was not there when the person left the home, the affidavit said.

The yard sign was “used to facilitate the concealment of the explosive device,” the affidavit said.

CNN’s Marlena Baldacci contributed to this report.