McALESTER, Okla. (AP) — A polygamist convicted of fatally stabbing his 11-year-old niece and dumping her body in rural Oklahoma was executed Thursday.

Jessie James Cummings Jr., whose personality was once compared to Charles Manson's, reiterated his innocence before being executed.

"The justice system let me down on this case. It turned a blind eye to truth in this," Cummings said. "Today, you came here to see an innocent man die."

He gasped twice during the six-minute execution and died at 6:11 p.m.

Cummings was convicted of killing Melissa Moody, whose skeletal remains were discovered near a Choctaw County bridge in 1991.

Prosecutors allege that Cummings mentally and physically abused his wives and children to maintain control over the women. It was not immediately known how many children Cummings had with at least three women known to have had relationships with him.