CHICAGO (AP) — A Chicago-based appeals court has revived a federal lawsuit brought against investigators by a former Indiana State Police trooper convicted twice but later acquitted of killing his wife and two young children.

The 7th U.S. Circuit Court of Appeals ruled Tuesday that David Camm, who spent 13 years in prison, could pursue damages for some of his constitutional claims, including that officials suppressed evidence that a forensics investigator wasn’t qualified.

A lower court tossed the lawsuit last year , finding Camm’s $30 million case hadn’t offered adequate proof for any claims. The 7th Circuit concurred with some of the lower court’s findings.

Jurors acquitted Camm in 2013 in the 2000 shooting deaths of 35-year-old Kim Camm, 7-year-old Brad and 5-year-old Jill. They were killed at their Georgetown home in southern Indiana.