Federal prosecutors have charged two men with possession of a pipe bomb found in their car on Saturday after they were arrested in connection with an early morning assault outside a St. Paul gas station.

Frederic Pittman III, 37, of Roseville, and Monttraill Lamar Claiborne, 40, of St. Louis, were arrested Saturday after police stopped their car and found the device. Several nearby homes were evacuated as a precaution.

Pittman and Claiborne have been in custody since their arrests. They made their first appearances on the federal charges Wednesday in U.S. District Court in St. Paul. Prosecutors charged each of them with one count of illegally possessing an explosive pipe bomb. Claiborne, who has multiple prior drug convictions in Missouri, is also charged with illegally possessing two pistols found during the traffic stop.

The incident started with reports that the driver of the car had threatened to shoot a woman outside a SuperAmerica gas station at 7th Street E. and Johnson Parkway. After responding to the call and stopping the car, St. Paul police discovered a bomb fashioned out of PVC pipe, according to a federal complaint signed by a special agent with the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF).

A person who lives near the gas station called in the complaint. The witness later described being awakened by yelling and seeing one man run to his car before pulling out a gun and pointing it at a woman. "Do it, do it, I ain't got nothing to live for. My brother's a Crip," the woman yelled, according to the complaint.

Police reviewed surveillance footage from the gas station, then stopped the two men near the intersection of Maryland Avenue and Lake Place. Police confiscated two pistols, one of which had been reported stolen in St. Louis in 2013. They found the pipe bomb inside a duffel bag in the trunk and called the city's bomb squad unit.

Terry Sauer, Star Tribune
Monttraill Claiborne

According to the complaint, the pipe had external end caps with a "hobby fuse" — often used in fireworks or improvised explosive devices — glued to one end. Officers later tested gray powder found inside the device which "reacted energetically in a manner consistent with a low explosive pyrotechnic powder."

It's unclear why they had the bomb, and, in interviews with police after their arrests, both men denied knowing that the explosive was in the trunk.

Claiborne told police he was a passenger in the rental car driven by Pittman and that he had been in Minnesota for less than 24 hours. Claiborne said a woman kicked their vehicle and verbally threatened the two outside the SuperAmerica. Both men also denied seeing the firearms that police seized.

Pittman said he had borrowed the rental car from a friend. However, an ATF officer found that Pittman was one of two people who rented the car in July and renewed the rental earlier this month.

Pittman identified one of the women he encountered at the SuperAmerica as an ex-girlfriend named "Bella," whom he confronted earlier that night at Augies bar in Minneapolis. He said the woman tried to assault him and warned that she would call the police and tell them he had a gun.

The men are scheduled to appear for a detention/preliminary hearing Friday.

Stephen Montemayor • 612-673-1755

Twitter: @smontemayor