Durham, N.C. — Authorities investigating the shooting of a North Carolina State Highway Patrol trooper last week found bomb-making materials in the Durham home of the man they've arrested in the case.

A Feb. 20 search warrant shows investigators seized PVC pipe, nails and other items from the apartment of Mikel Edward Brady, of 800 White Pine Drive, Apt. 1205.

In an earlier search of the home, according to the warrant, police found a digital camera with "clear pictures of instructions marked how to make bombs," as well as a large map of Durham on the bedroom wall with locations of police, fire and EMS stations marked.

After reviewing the photos with the FBI, they returned to the apartment specifically to look for materials used for bombs.

They also seized, according to the warrant, salt, a toolbox, a scale and items identified only as a "small black metal tube," "metal parts with hole drilled in center" and "reactive targets."

Brady, 23, is in the Durham County jail under an $8 million bond for the Feb. 18 shooting of state trooper Michael L. Potts during a traffic stop on U.S. Highway 70 in Durham.

Authorities say Brady shot Potts from the driver's seat at an "extraordinarily close" range. Potts, who was released from a local hospital on Thursday, was hit in both of his hands, right shoulder and the right side of his face.

Brady fled the scene but was arrested the following morning on a charge of assault with a deadly weapon with intent to kill inflicting serious injury.

His pregnant girlfriend, Lyndsey Smith, 21, was arrested Feb. 20 on charges of accessory after the fact to assault with a deadly weapon and harboring a fugitive. She is in jail under a $1.5 million bond.

The two moved to Durham two months ago from Vermont, where Brady had served 33 months in prison on numerous charges stemming from several burglaries and a home invasion.

Bill Soule, district manager for the probation and parole office that oversaw Brady's case, said he also served time in federal prison for possession of stolen explosives. The conviction stemmed from a dynamite theft at a local rock quarry in which Brady and three others tried to sell the dynamite for drugs.

Soule said Wednesday there was no other indication that Brady had a history with explosives and that he was surprised by the new accusation.

"He's a guy who was a burglar. The home invasion was the most serious offense here in Vermont," he said.