AUSTIN (CBSDFW.COM/AP) — The FBI has determined the man suspected in a series of bombings in Austin last year had no known links to international terror groups or domestic hate groups.

Court documents filed by the U.S. attorney’s office say an FBI investigation found that 23-year-old Mark Conditt had no accomplices or any “recognized ideology” when he launched the deadly attacks on March 2.

Austin police say Conditt died after he set off an explosive device inside of his vehicle in a suburban Austin hotel parking lot as SWAT teams closed in.

The explosions killed two people and seriously injured four others after bombs were left outside homes and along a public trail. Another exploded at a FedEx distribution center in San Antonio.

Conditt was tracked down using store surveillance video, cellphone signals and witness accounts of a customer shipping packages in a disguise that included a blond wig and gloves. Police finally found him at a hotel in Pflugerville, about 17 miles northeast of Austin.

Police say Conditt blew himself up on March 21, as officers closed in to make an arrest.

A 25-minute cellphone video left behind by the bomber details the differences among the weapons he built and calling himself a psychopath. Police say amounts to a confession.

Police say the video amounts to a confession, but a motive for the bombings remains unclear.

(© Copyright 2019 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)