BRIGHTON, Colo. (AP) — A man accused of killing two 16-year-old boys after friends say the boys tried to blackmail him has pleaded not guilty in Colorado.

William Otto of Brighton faces charges of first-degree murder, contributing to the delinquency of a minor and tampering with evidence. He appeared in Adams County court Tuesday.

Gustavo Espinosa-Gamboa was shot three times in the head and once in the chest, and Jonathan Gonzalez died from one shot to the head.

The teens’ bodies were found buried in August in the small farming town of Sedgwick, about 150 miles from their neighborhood in unincorporated Adams County. The boys lived near Otto.

Authorities say Otto killed the teens after they allegedly tried to blackmail him with a cellphone video. An arrest affidavit says the video showed Otto asking at least one of them for a sex act.