The man called two women in Greensburg in December, fraudulently telling each he had abducted a relative and using specific names in each case, Police Lt. Robert Stafford said.
Both women called police, and one tracked down the supposedly missing relative on her own.
Authorities believe the prank caller is finding victims in local death notices, searching for women who have recently lost husbands and using the listed names of relatives as bait, the Pittsburgh Post-Gazette reported Wednesday.
Stafford said the police do not yet know the man's identity.
"We're trying to track some numbers down. The more information we have, the better," Stafford said.