MINNEAPOLIS (AP) -- Authorities say a Stillwater man admitted to strangling his girlfriend at her St. Paul home last summer and then inserting a cocaine-laced straw in her nose to make her death look like an overdose.

Reports say 34-year-old Ivan Walker pleaded guilty Friday in Ramsey County District Court to the second-degree unintentional murder of 39-year-old Shana Branch. He also pleaded guilty to first-degree criminal sexual assault of a teenage house guest who was sleeping on Branch's couch the night of the killing.

Branch's sons, ages 20 and 7, were in the home at the time of the attack and one of them called 911.

Ramsey County prosecutors say Walker will be sentenced in April to 30 years in prison as part of a plea agreement.