Florida man arrested for allegedly placing bomb at veterans hospital The FBI is assisting in the case.

A man in Florida was arrested for allegedly placing an improvised explosive device (IED) outside of a Veterans Administration hospital in Bay Pines.

Mark Edward Allen, 60, allegedly made the explosive device found at the hospital, as well as an IED found at a home in St. Petersburg, Florida, according to court documents. He made his initial court appearance on Tuesday.

Allen is charged with possession of an unregistered destructive device.

Tampa police found the IED at the hospital on May 29. Later, Allen’s wife later called the St. Petersburg police and told them that her husband had made a bomb. While he was sleeping, she drove the IED to a friend’s house because she was "scared,” according to court documents.

Allen, a U.S. Army veteran, was captured on surveillance video allegedly placing the IED at the hospital, prosecutors say.

Both bombs were discovered and disabled, according to authorities.

Upon review of the forensic analysis of both bombs, law enforcement officials allege that both explosive devices matched each other, and were created by Allen.

Danny Defenbaugh, the former FBI special agent in charge of the Oklahoma City bombing investigation and an explosives expert, told ABC News that explosive devices made by the same person often carry a "signature."

"There are certain things, such as the way the wire is twisted or the insulators are saved, that they could be different in that bomber's signature," Defenbaugh said.

The IED's found in Florida had a "9 volt battery, electrical wires, an improvised initiator, an unknown powder and a clothespin switch,” according to the indictment.

The Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) told ABC News that it is assisting local police in the case. The FBI is also collecting evidence.

“ATF provided expertise and technical assistance in the mechanical disassembly of these destructive devices for further evidentiary processing,” the ATF said in a statement.

Allen made his first court appearance on Tuesday and is being held without bail pending trial.