Handout image obtained on June 30, 2009 from WireImage shows Michael Jackson during rehearsals for planned shows at Staples Centre in Los Angeles, 23 Jun 2009

The head of a concert promotion agency says a tribute to late pop star Michael Jackson will likely be held at the Staples Center arena in Los Angeles.

Randy Phillips, head of the promotion company AEG Live, said Thursday that the family is considering holding the event on Tuesday but has not made a final decision.  He said admission will be free.

AEG Live was the company producing a series of "comeback" concerts featuring the late star, which were set to begin this month in London. Now it is expected to produce the memorial event, after Jackson's sudden death on June 25.

Also Thursday, the biological mother of Jackson's oldest two children hinted that she may press for custody. Debbie Rowe told a Los Angeles television news program that she wants her children.

But her lawyer said later that Rowe has not reached a decision about asking for custody. Jackson asked in his will that his 79-year-old mother be made their guardian.

And U.S. media report the Drug Enforcement Administration (DEA) has joined the investigation into Jackson'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.

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.

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.

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