LOS ANGELES (Reuters) - Hours after a child welfare agency memo surfaced saying that earlier this year Michael Jackson had been cleared of allegations that he molested a 13-year-old boy, Los Angeles police officials on Tuesday said they had almost no involvement in that investigation.

And Santa Barbara prosecutors -- who are expected to charge Jackson with child molestation next week following their own probe -- said they did not expect the prior investigation to be "significant" to their case.

The Los Angeles County Department of Children and Family Services memo, which was first made public by The Smoking Gun Web site (http://www.thesmokinggun.com), said that the agency and the LAPD had determined in February that there was no basis for the allegations against Jackson.

"The investigation by the Sensitive Case Unit concluded the allegations of neglect and sexual abuse to be unfounded both by the LAPD-Wilshire Division and the Department," said the memo, which was dated Nov. 26.

A DCFS spokesman told Reuters that the memo was genuine and that the agency had investigated Jackson.

"The document is authentic and our department is investigating how it was leaked," spokesman Neil Zanville told Reuters, adding that California state laws regulating child welfare prohibited him from commenting further.

But in a strange twist, Los Angeles Police officials said in a written statement that their involvement in the investigation consisted of a failed bid to interview the boy and his family.

BOY COULD NOT BE FOUND

"A Los Angeles Police Department detective accompanied a DCFS caseworker to make contact with the child at an address that had been provided to DCFS," the statement said. "The child and his family could not be located at the address.

"The Department of Children and Family Services no longer required the assistance of the Los Angeles Police Department," the statement said. "The Los Angeles Police Department had no further involvement in this matter."

A spokesman for the LAPD declined to elaborate on the apparent contradiction between the two accounts.

Meanwhile, Santa Barbara County District Attorney Tom Sneddon and Sheriff Jim Anderson said in a joint statement that they were aware of the Los Angeles investigation before they proceeded with their own case against Jackson.

"Given what we know, we do not consider the DCFS statement a significant factor," they said.

Jackson, who was released on $3 million bail, has called the allegations a "big lie." His attorney, Mark Geragos, could not be reached for comment.

Los Angeles authorities began their investigation after a British TV documentary in which Jackson said he shared his bed with children. But according to the memo, the boy's mother told investigators "the media had taken everything out of context."

The 45-year-old singer, who lives at the sprawling Neverland Valley Ranch in the hills above Santa Barbara, is not named in the memo and is identified only as "the entertainer."

"As per the sexual abuse allegations, the mother stated that her children are never left alone with the entertainer," the memo says. "She further stated that her son has slept in the same room as the entertainer but they did not share a bed. The entertainer would sleep on the floor."

The boy and his brother denied any abuse to investigators and "both children expressed a fondness for the entertainer and stated they enjoyed visiting his home, where they would often ride in the park, play video games and watch movies."