Police in Vallejo, California, found the body of 28-year-old Renia Lewis behind a hidden attic entrance, nearly a week after she went missing.

Douglas Irwin Shaw, 41, has been arrested and admitted responsibility for her murder, though authorities have not disclosed a motive or whether the two knew each other.

Lewis was last seen Friday evening but wasn’t reported missing until Sunday; investigators connected her to a home and discovered her remains during a thorough search, Fox News has reported.

Vallejo Police Chief Jason Ta called the crime “heartbreaking” and praised officers for solving the case. Lewis’ death is the 14th homicide in Vallejo this year.