Federal prosecutors dropped the criminal case Monday against a man from Long Beach arrested following the fatal bombing of an Aliso Viejo beauty salon.

Stephen William Beal was released from federal custody early Sunday morning.

He had been accused in a criminal complaint of possessing an unregistered destructive device after federal agents said they discovered explosive materials during a search of Beal’s home and garage.

"Further examination by the Federal Bureau of Investigation raises questions as to whether the devices meet the statutory definition for a 'destructive device,'" prosecutors said in a new court filing.

Prosecutors contacted the case judge over the weekend.

"We prepared the motion very soon after learning the new information and brought it to the judge soon after," said U.S. Attorney’s Office spokesman Thom Mrozek.

The search of Beal's home began hours after an explosion April 15 at a medical office building on Mareblu that killed 48-year-old aesthetician Ildiko Krajnyak-Vestil, law enforcement officials said.

Beal was in business with Krajnyak-Vestil and the two had recently ended a romantic relationship, friends and authorities confirmed.

Beal was ordered held without bail last week after federal prosecutor convinced a judge he was a potential danger to society.

U.S. District Court Magistrate Judge Karen Scott cited Beal’s, "knowledge of explosive construction," and that he "built explosives found at home," as reasons for denying bail.

Beal voluntarily called authorities after he learned of the bombing and talked to investigators at length that night. He told agents the explosives were in reality components he had used in a model rocketry hobby and that they had no sinister purpose, according to federal court documents.

Beal was never accused of involvement in the Aliso Viejo bombing.