Michael Jackson (Feb 2005 file photo)

U.S. media report the Drug Enforcement Administration (DEA) has joined the investigation into pop star Michael Jackson's sudden death on June 25.

Reports say the Los Angeles Police Department in the western state of California asked the federal drug agency to help find out what caused the 50-year-old singer's death.

Investigators removed two large bags of medical evidence from Jackson's rental home, where an emergency caller reported that the pop icon had stopped breathing.

There is speculation that prescription medications may have led to the singer's death.

A medical examiner found no external signs of foul play and investigators are now waiting for the results of toxicology tests, which are expected to take weeks.

Separately, a Jackson family spokesman says memorial plans are under way, but said a public service will not be held at the late singer's Neverland Ranch.

On Wednesday, Jackson's 2002 will was filed in court and estimated his fortune to be worth $500 million at the time, with the estate to be put into a family trust, and guardianship of his three children: 12-year-old Prince Michael, 11-year-old Paris Michael Katherine, and seven-year-old Prince Michael II, to be granted to Jackson's mother Katherine, 79.

Jackson's will says he "intentionally omitted" his former wife, Deborah Rowe Jackson, who is the mother of his oldest two children.  The youngest child was born to a surrogate mother.

Jackson died as he was preparing to launch a series of 50 sold-out comeback concerts next month in London.


Some information for this report was provided by Reuters & AP.