Pop star Michael Jackson rehearses for his planned shows in London at the Staples Center in Los Angeles, California in this handout photo taken June 23, 2009 and released June 29, 2009. Jackson, 50, died suddenly of cardiac arrest at his rented Los Angeles home on June 25, just a few weeks before the planned string of 50 comeback concerts in London. (Xinhua/Reuters Photo) Photo Gallery>>>

    LOS ANGELES, July 2 (Xinhua) -- Coroners and family members alike are still trying to sort out the major issues arising from the death of troubled pop star Michael Jackson exactly one week after he died, sources close to the investigation said on Thursday.

    Jackson was announced dead last Thursday after suffering a heart attack at his rented home in a wealthy Los Angeles suburb.

    Among the issues remaining to be sorted out are the cause of Jackson's death. There have been reports that Jackson dabbled with some highly dangerous medications, but the Los Angeles Coroners Office said it won't be known for weeks, until toxicology tests are completed.

    When and where Jackson will be buried is not yet known. Plans for a public memorial befitting "The King of Pop" haven't been announced. And just who ultimately will have custody of his children and control of his estate likely will not be resolved until after extensive litigation.

    One thing has become clear, however. Even though fans have gathered at Neverland, the ranch Jackson once owned in Santa Barbara County, no burial or memorial will be held there.

    Officials in Santa Barbara County said that representatives of Colony Capital LLC, the company that acquired the ranch last year as Jackson's finances spiraled out of control, had approached them on Tuesday about a burial there.

    But after examining regulations on burials on private land, the representatives were told that the necessary approvals would take "months, not weeks," Michael Ghizzoni, the county's attorney, said.

    Discussions for a public memorial are focusing on a possible event next week at Staples Center, in downtown Los Angeles, according to the Los Angeles Times on Thursday.

    A family spokesman told the paper, however, that no plans had been finalized, and the event was still a proposal that had not been approved by the Jacksons.

    A will signed by Jackson in 2002 was filed in Los Angeles Superior Court on Wednesday, specifying he wanted his mother to be the guardian of his three children. But if she were to die before him, he asked that singer Diana Ross be appointed. Katherine Jackson is 79; Ross is 65.

    Despite the filing of the will, which designated an attorney and music-industry executive as executors of the will and estate, Los Angeles Superior Court Judge Mitchell Beckloff ruled that Jackson's mother will remain the special administrator of the singer's estate pending another hearing on Monday.

    Beckloff said he saw no urgency to remove Katherine Jackson for now and that he wanted to see if additional wills are filed between now and Monday.

    The judge said he named Katherine Jackson special administrator three days ago in large part to protect her son's memorabilia, which recently was the subject of an attempted auction and a lawsuit before the dispute was settled out of court.

    The will that surfaced on Wednesday names attorney John Branca and music executive John McClain as executors. Through their attorney, Paul G. Hoffman, they sought to have Monday's order naming Jackson's mother special administrator vacated, saying it was based on the false assumption the entertainer had no will.

    According to the five-page will and a series of probate documents filed with it, Jackson's estate is believed to be worth more than 500 million dollars. The singer, who died last Thursday at age 50, left his holdings to the Michael Jackson Family Trust, and named his mother and children as beneficiaries.

    The will was signed by Jackson on July 7, 2002. In it, he names Branca, McClain and his accountant, Barry Siegel, as executors. Ina letter dated Aug. 26, 2003, however, Siegel resigned as a co-executor of the will.

    In the will, Jackson specifically leaves his former wife, Deborah Rowe, out of any inheritance.

    On Monday, Beckloff granted temporary custody of the children --Prince Michael Jr., 12; Paris Michael Katherine, 11; and Prince Michael II, 7 -- to Jackson's mother. The two older children were delivered by Rowe, and the youngest by a surrogate mother whose name has never been revealed.

    Rowe is reported to be considering challenging Katherine Jackson's bid for permanent custody, but she has yet to signal her intentions. Eric George, her lawyer, told the Los Angeles Times he will be at a custody hearing next Monday to represent her, but did not know whether she would ask for custody or to continue to have visitation rights.