COLUMBUS, Ohio – A claim by an Ohio death row inmate that he committed an unsolved murder more than two decades ago will be investigated, a prosecutor said Thursday.

Richard Cooey is scheduled to be executed Oct. 14 for killing two University of Akron students in 1986. He told prison employees one day before his scheduled execution in July 2003 that he killed a man who beat up his sister but was never prosecuted for it.

Sherri Bevan Walsh, prosecutor for Summit County, said she hadn't known about Cooey's claim until an Associated Press reporter who had viewed corrections documents earlier asked her about it Thursday. She said she has no choice but to ask police to investigate the allegation.

“Any time somebody says that they committed a murder, we are going to take that seriously,” Walsh said.

“We have no way of knowing whether or not Richard Cooey is just blowing smoke and making things up or whether he did in fact did kill somebody else more than 20 years ago.”

Cooey's attorney Eric Allen said he needs to study the claim before commenting.

If executed, Cooey would be the first inmate to be executed in Ohio after the U.S. Supreme Court reviewed Kentucky's lethal injection procedure last year.

Cooey, 41, made the comments about killing a man he described as a hockey player while at the Southern Ohio Correctional Facility awaiting his execution the following day, according to documents obtained by the AP. The allegation was not investigated at the time.

A federal judge granted Cooey a last-minute reprieve from execution.

In a federal lawsuit filed earlier this month, the 267-pound Cooey argued he is too fat to be put to death and that his weight could diminish the effectiveness of one of the lethal injection drugs.

The Ohio Parole Board will announce Tuesday whether it will grant Cooey's request for clemency. The board denied a similar request in 2003.

The new investigation has no effect on Cooey's federal lawsuit, said Jim Gravelle, spokesman for Ohio Attorney General Nancy Hardin Rogers.

Should Walsh's investigation turn something up and she files new charges, “we would be happy to sit down and talk to her,” Gravelle said.