A judge has declared a mistrial in the case against a Spokane Valley man who was facing up to 50 years in prison following an attack on his ex-girlfriend and his former best friend.

Superior Court Judge Jerome Leveque declared the mistrial Wednesday after a witness offered testimony that the defense said was a surprise.

The witness said defendant Don R. Davis, 29, admitted possessing a gun that investigators said was used in a drive-by shooting as part of the case.

Defense attorney Rob Cossey objected because that information had not been presented to him by the witness or by Deputy Prosecutor Gayle Ervin in preparation for the trial.

“It was completely out of the blue. It was out of the witness’s mouth before I could do anything,” Cossey said. “I asked for a mistrial and the judge granted it.”

Davis is expected to plead guilty to some of the charges on April 6.

“We think we can reach a resolution,” Cossey said, “but it doesn’t include the attempted murder charges.”

Ervin had charged Davis with 10 criminal charges, including two counts of attempted first-degree murder, following a series of events that began on Oct. 4, 2009, with wild vehicle chase on Interstate 90 that included several collisions as Davis attempted to force his former best friend, Clayton Cooper, off the roadway, according to court testimony.

Davis was also charged with breaking into an apartment and stealing a shotgun that witnesses said was used in a drive-by shooting. Just minutes after that event, deputies conducted a search warrant and found the stolen gun in the trunk of the car Davis was driving, according to court testimony.

If convicted of all charges, Davis faced as much as 411 months in prison plus about 200 months for the weapons charges.