STARKE, Fla. – A former police officer who murdered nine people during a 1986 crime spree was executed Tuesday after his attorneys' last-minute appeals were rejected.

Manuel Pardo, 56, was pronounced dead at Florida State Prison at 7:47 p.m., about 16 minutes after the lethal injection process began. His attorneys had tried to block the execution by arguing that he was mentally ill, but federal courts declined to intercede.

Reporters could not hear his final statement because of an apparent malfunction in the death chamber's sound system. A white sheet had been pulled up to his chin and IV lines ran into his left arm. He blinked several times, his eyes moved back and forth and he took several deep breaths. Over the next several minutes the color drained from his face before he was pronounced dead.