Police in Sacramento, California, have arrested a 37-year-old man in connection with the brutal rape and murder of a 20-year-old autistic woman who went out for a walk on Jan. 27 and was never seen alive again. Sacramento County Sheriff’s Chief Deputy Jim Barnes announced the news at a press conference late Friday, several days after the body of Emma Roark was found in a secluded area near the American River. Police say DNA evidence led them to Mikilo Morgan Rawls, a transient with a lengthy rap sheet. The circumstances surrounding Roark’s murder remain unclear. Authorities say she left her home to go for a walk around noon on Jan. 27 but never made it back. A GoFundMe organized by her mother to help locate her immediately after her disappearance noted she was “at risk with Autism.” “She went for a walk to the river and never came back,” the GoFundMe said. After police announced the arrest, Roark’s mother, Celeste, shared the news on Facebook, writing: “This is the monster who killed my daughter. May he never have a moments rest in prison.” Police described Roark’s death as “a very gruesome crime” perpetrated by a “type of evil,” but they declined to provide further details on the killing. “You can’t unsee this. This is as bad as it gets,” Barnes told reporters.