Ohio Department of Rehabilitation and Correction, File, Associated Press
FILE- This undated file photo provided by the Ohio Department of Rehabilitation and Correction shows Arthur Tyler. Cuyahoga County Prosecutor Tim McGinty planned Monday, April 21, 2014, to submit his position on whether condemned killer Tyler, who is facing execution next month for a Cleveland produce vendor’s 1983 slaying, should receive mercy. Attorneys for defendant Tyler say he should receive clemency partly because a second defendant repeatedly admitted being the shooter.

COLUMBUS, Ohio — Lawyers on opposite sides of capital punishment have found common ground in the case of a condemned Ohio inmate they agree should be spared, though for different reasons.

Attorneys for death row inmate Arthur Tyler told the Ohio Parole Board Thursday their client is innocent and should be freed based on statements by a co-defendant. Cleveland prosecutors planned to argue that Tyler's sentence should be commuted to life without parole because of questions about the conviction.

Tyler, 54, is scheduled to die May 28 for the 1983 killing of Cleveland produce vendor Sander Leach during a robbery.

Tyler's first death sentence was overturned by a state appeals court in 1984 on the basis of poor legal assistance. He was convicted at a second trial and again sentenced to death.

Tyler's co-defendant, Leroy Head, pleaded guilty for his role in the slaying and was sentenced to life in prison with parole after 20 years for aggravated murder and seven to 25 years for aggravated robbery, according to court and parole board records. He was released from prison in 2008.

Head made two statements to police that the gun went off while he was struggling with Leach and that it was he, not Tyler, who was responsible for the shooting, according to Tyler's clemency request.

Head recanted those statements and testified against Tyler at the first trial, saying Tyler had threatened his family if he explained what happened that day. Head also testified at Tyler's second trial.

In later years, Head denied Tyler had ever threatened him and said he testified at the second trial because a prosecutor threatened to negate his plea deal, according to Tyler's parole board filing.

Head also made multiple statements to defense attorneys, fellow inmates and others that Tyler was not the shooter, according to the clemency request.

"Head signed a handwritten statement saying that he, not Arthur Tyler, shot the old man," the filing said, referring to a parole board exhibit dated April 27, 1986.

There is "grave doubt" about Tyler's guilt, federal public defender Vicki Werneke told the parole board Thursday.

"We will show the system has been unfair to Arthur Tyler throughout this process," Werneke said.

Messages left at a Cleveland phone listing for Head were not returned. A message was left with his attorney from his original trial.

Cuyahoga County Prosecutor Tim McGinty says the case doesn't meet current legal standards for a death penalty prosecution.

The only options under Ohio law in 1983 for jurors sentencing Tyler were death or life with parole after 20 or 30 years, McGinty said. Those limited options may have led to a death sentence, McGinty said in a filing with the Ohio Parole Board.

Ohio lawmakers added life without parole as an option in 1996, after which death sentences in Ohio began to decline.

McGinty opposes efforts to free Tyler, saying he is "far from innocent" and his participation in the killing can't be questioned.

However, McGinty added, "Head's evolving statements are cause for concern, and while it does not negate Tyler's guilt, it may undermine public confidence in Tyler's sentence."

The parole board makes a recommendation to the governor, who has the final say.

Last year, in a rare move, McGinty asked the board to spare death row inmate Billy Slagle for fatally stabling neighbor Mari Anne Pope in 1987 during a Cleveland burglary while two young children were present.

McGinty said that jurors today, with the option of life without parole, would have been unlikely to sentence Slagle to death.

The parole board and Gov. John Kasich both rejected mercy for Slagle, who later committed suicide a few days before his execution.

Andrew Welsh-Huggins can be reached on Twitter at https://twitter.com/awhcolumbus