Updated

A drill bit found in Terry Nichols' (search) home was used to drill a hole in a lock at a quarry where explosives like those used in the Oklahoma City bombing were stolen, a witness testified Wednesday at Nichols' state murder trial.

James Cadigan, a retired FBI toolmark examiner, is the latest witness to be questioned by prosecutors seeking to link Nichols to the April 19, 1995, bombing of the Alfred P. Murrah federal building (search) that killed 168 people.

Cadigan said the one-quarter inch drill bit made the same distinctive markings as those found in a drilled hole in a padlock found at a Martin Marietta quarry near Marion, Kan., where detonation cord and blasting caps were stolen less than seven months before the bombing.

"That was the drill that was used," Cadigan said.

FBI agent Thomas Brown of Wichita, Kan., testified that he seized a cordless drill from Nichols' basement in Kansas during a search three days after the bombing.

The quarry was 25 miles from Nichols' home in Herington, Kan.

Prosecutors allege Nichols and Timothy McVeigh (search) worked together to gather components for the bomb and build it. McVeigh was executed for the bombing.

Nichols is already serving a life sentence on federal charges in the deaths of eight law enforcement officers. The state charges are for 160 other victims and a fetus of one of them, and prosecutors are seeking the death penalty.

Prosecutors say detonation cord and blasting caps were among the components used in the 4,000-pound ammonium-nitrate-and-fuel-oil bomb that destroyed the federal building.