WARSAW, Mo. (AP) — A man already in prison on drug charges was convicted of raping and killing a 15-year-old rural Greene County girl and dumping her body in Truman Lake.

A Cooper County jury on Thursday convicted Anthony Balbirnie in the September 2012 death of Khighla Parks. He will be sentenced Sept. 1 for second-degree murder and other charges.

Prosecutors say Balbirnie choked Parks during sex at a home in Buffalo then dumped her body in the lake near Warsaw.

Balbirnie is awaiting trial for second-degree murder in the 2008 death of Theresa Mohler, of Springfield. Investigators believe Balbirnie held Mohler against her will for several days at his home in Polk County. She allegedly was forcibly injected with meth and raped before escaping. Prosecutors say the injection caused a fatal infection.