ST. LOUIS (AP) — A Missouri death row inmate with a July scheduled execution is asking Gov. Jay Nixon to appoint an independent panel to review his clemency request.

Fifty-four-year-old John Middleton is scheduled to die July 16 at the state prison in Bonne Terre. The one-time methamphetamine dealer was convicted in the 1995 drug-related killings of three people in northern Missouri.

The petition for an independent Board of Inquiry says the governor cannot impartially rule on Middleton's request to commute his death sentence since Nixon was the state's attorney general when Middleton stood trial.

That alternative is allowed under Missouri law but has been rarely invoked, most recently in 1997 by former Gov. Mel Carnahan. He convened a similar panel three years earlier, but Nixon has rejected similar requests as governor.