PHILADELPHIA (AP) — A pot dealer who confessed to killing four men on his family’s Pennsylvania farm last week also claimed to have killed two people in Philadelphia, but the city’s police commissioner called the information “sketchy.”

Police Commissioner Richard Ross says Philadelphia detectives are looking through their files to check on the claims made by 20-year-old Cosmo DiNardo but that Philadelphia detectives have not had a chance to question him.

DiNardo was charged last week in Bucks County with four counts of first-degree murder in the case of four missing men. Ross says he also claimed that he killed a man and a woman in Philadelphia years ago but did not know their names.

Philadelphia police say Bucks County authorities are still investigating DiNardo’s statements. The Bucks County district attorney declined to comment beyond court papers released last week, which don’t mention the Philadelphia claims.