Officers responded to a child sexual assault investigation in the 200 block of North Langstaff Street around 3 p.m.
During the investigation, officers learned an adult male living at the location had sexually assaulted the minor.
The suspect was later identified as Ebelio DeLeon, 38, of Lake Elsinore. He was arrested and booked for sexual assault at the Southwest Detention Center on July 9.
Investigators believe there may be more alleged victims since the residence where the sexual assault took place was used as an unlicensed day care facility.
Anyone with information about this case was urged to contact Detective Ryan Deanne or Investigator Callahan at the Lake Elsinore Police Department at (951) 245-3300.