McDonald's house was served with a search warrant on Tuesday night after the department received a call from a local hospital regarding the alleged victim, who was receiving treatment.
Damian Trujillo of NBC Bay Area News first reported the news.
McDonald was named as a suspect after a preliminary investigation. No arrests have been made and the investigation is ongoing.
McDonald, 30, was cleared in November after an investigation into an alleged domestic violence incident at his home.
He was arrested on Aug. 31 on suspicion of felony domestic violence. Police said that McDonald was celebrating his birthday at his home with friends and teammates. When police arrived at the home, they said the alleged victim, McDonald’s fiancée, had "visible injuries."
After the investigation, the district attorney said it did not find sufficient evidence to press charges and characterized it as a "physical struggle between two parties, each party blaming the other."
In September, police revealed an earlier incident that occurred at the home of McDonald and his fiancée. In May, police had been called to the home due to a dispute between a man and a woman in which the woman eventually pulled a gun on the man.
McDonald continued to play throughout his investigation, as 49ers coach Jim Harbaugh and CEO Jed York both said they would not discipline McDonald until there were further developments in his case.
- Molly Geary