Police say they have not discovered a clear motive for the bombings of three buildings in Provo and Orem.

But officers found evidence during a Thursday search that links two of the incidents, said Provo Police Chief Swen Nielsen.Police held a press conference Thursday to describe the investigation that led to the early morning arrest of Jim D. Bowcutt, 32, 472 N. 400 West, Orem. Bowcutt was arrested around 3 a.m. at his apartment and booked into the Utah County Jail for investigation of constructing, possessing and placing of an infernal machine.

Nielsen said evidence establishes "to some degree a relationship" between a bomb found at the Orem City Library Jan. 27 and one found Feb. 17 at the Wasatch Mental Health Center, 600 E. 300 South. Nielsen would not elaborate on the connection between the two incidents.

However, he did say that a similar link has not been found to a bomb placed at an LDS chapel on April 14. That bomb exploded, unlike the previous two bombs, causing moderate damage to a window and curtains.

Nielsen credited Provo detectives Dave Bolda and Richard Healey with using "good old-fashioned police work" in the case.

The two detectives were assigned to the case after the April 14 bombing. They combed sales receipts at Radio Shack and other electronic parts stores, looking for purchases of components that could be used to construct a bomb.

During that search, police said, receipts with the same name on them turned up repeatedly. Wednesday night officers obtained a search warrant.

"A series of pieces taken together and looked at in a holistic way led us to the suspect," Nielsen said.

Police evacuated residents of the neighboring apartment before the Special Response Team led by Sgt. Tom Nielsen forced entry. The special team was used because of fears that arresting officers might be in danger, Nielsen said.

Sgt. Brad Leatham, the department's explosives expert, said the electronics used to build the bombs was "highly sophisticated."