The U.S. Supreme Court has declined the appeal of an Ohio inmate who has long maintained his innocence in the 1994 slaying of three people.

The court's Tuesday decision involves the case of Kevin Keith. He is serving a life sentence for killing two women and a 4-year-old girl in what prosecutors said was retaliation for his arrest in a drug sweep.

Lawyers for Keith say the personnel file of a state forensics investigator who worked on his case contains allegations she had a habit of providing police departments answers they wanted in cases.

Attorneys for the 54-year-old Keith, who is black, also say the file shows the investigator used racial slurs against co-workers.

Prosecutors say there's no evidence the file would have made a difference at trial.