A Twin Cities man pleaded guilty Monday to killing a woman last year and leaving her 7-year-old son to find her body.

Sammy D. Henderson, 25, who has no known address, pleaded guilty in Ramsey County District Court to second-degree murder with intent in the death of Sherell Montrese Craighead, 30. He originally also faced a charge of first-degree murder while committing criminal sexual conduct.

According to the complaint: Craighead’s son went to his grandmother’s house about 7 a.m. Sept 1 and went to sleep. When she later asked why he had come over, the boy said his mother “was sleeping naked on the floor and bleeding from her back.”

The grandmother and boy returned to Craighead’s apartment, where they found her rigid with rigor mortis.

Henderson told police that he and Craighead were casual sex partners, according to charges. He told police he forced her to have sex on Aug. 31 even though she told him to stop, the complaint said.

Henderson later admitted that he grabbed her neck with his left hand during sex.

“He let her go and she ‘just hit the bed’ and let out a short grunt without saying anything else,” the charges said. “Henderson said she was right on the edge of the bed and thought she could have rolled off it” because he heard a thump.

The Ramsey County medical examiner’s office ruled her death a homicide caused by asphyxia due to manual strangulation.

Henderson is scheduled to be sentenced on July 15.