A Florida man pleaded guilty on Monday to sexually abusing a 13-year-old girl who was murdered last year.

Stephan Sterns, 38, also pleaded no contest to murdering Madeline Soto, his girlfriend’s daughter. WFTV reported that Sterns’ pleas came a day before he was to stand trial for child sex crimes concerning Soto.

Soto vanished on February 26, and Sterns claimed he dropped her off at school that day. However, Orange County Sheriff John Mina said they now believe that wasn’t true and that “she was already dead at the time and that Stephan Sterns moved her body in the early morning hours on that day.”

Soto was allegedly seen discarding a child’s items in a dumpster the morning of Soto’s disappearance. Authorities reportedly found a laptop and backpack in the dumpster.

On March 1, Soto’s body was reportedly found in a wooded area in Osceola County. Sterns was reportedly in the area changing a tire just days prior. An autopsy determined she was strangled.

Video evidence of Sterns raping Soto was discovered in his phone during the teen’s disappearance. The abuse reportedly started when Soto was eight.

WFTV reported that plea negotiations — which Soto’s family approved — started last week. Sterns possibly faced execution if convicted of Soto’s murder.

[Feature Photo: Orange County police]