Investigators are searching pop star Michael Jackson's Neverland Ranch in California Tuesday, but the purpose of the search has not been disclosed.

Police say authorities executed a search warrant at the musician's sprawling home outside Santa Barbara. The Santa Barbara District Attorney's office is also involved, and the investigation is in connection with a criminal matter, police said. Media reports say no charges have been filed yet.

Jackson's spokesman was not immediately available for comment.

The search coincides with Tuesday's release by Epic Records of Number One, a greatest hits collection featuring Jackson's new single, "One More Chance."

The singer saw his career collapse in 1993 amid allegations he molested a young boy. Jackson has maintained his innocence, and charges were never filed. He reportedly paid a multi-million dollar settlement to the boy's family.