LOS ANGELES – "Heal the world. Make it a better place for you and for me." So sang Michael Jackson in his mega-selling 1992 anthem for change.

Now the singer's estate and Jackson's mother could use a little healing themselves as they fight each other over the non-profit Heal the World Foundation, which claims it's the successor to the pop star's defunct charity inspired by the song. At stake in the skirmish are trademarks worth millions of dollars and a piece of Jackson's legacy.

The dispute, which is playing out in a federal court in Los Angeles, is the latest example of the sometimes strained relationship between Jackson's family and his estate, which has already earned hundreds of millions of dollars.

But the fight against the new incarnation of the Heal the World Foundation has also raised questions about which causes the singer would want to focus on if he hadn't abandoned his charity to fight off allegations of child sexual abuse.

His mother, Katherine Jackson, left little doubt about her sentiments in a recent court filing: "It is not my desire, nor would it be the desire of my son Michael, to continue this lawsuit against Heal the World Foundation."

Her attorney, Perry R. Sanders Jr., said Friday that Katherine Jackson supports the charity but hopes that a more civil relationship between her and the estate can be restored. Sanders was hired late Thursday after Katherine Jackson's former attorney publicly cast doubts about the authenticity of her filing.

"Bottom line — I am going to do anything in my power to try to tone down the rhetoric that has happened to date to the extent possible," Sanders said.

Last year, Jackson's mother and father joined Heal the World's board of directors and placed their three grandchildren on a youth board. Jackson's mother and his children were prominently featured on a recent "Good Morning America" story that also included footage of Heal the World giving a $10,000 donation to a shelter in Los Angeles.

It was a high-profile plug for an entity that according to tax filings reviewed by The Associated Press has done little fundraising or charitable giving, but has fought to stake its claim to several Jackson-related trademarks and likeness rights that the singer's estate maintains it should own.

Jackson's estate wrote in a statement to the AP that the new Heal the World Foundation "has no relations to Michael Jackson's charity that touched so many lives before becoming inactive several years before Michael's death."

The estate did not say whether Katherine Jackson's involvement with the charity was costing the estate money, but said the "costs would be far greater if the estate did nothing to protect (Michael Jackson's) name and his trademarks because others would be profiting from intellectual property that rightfully belongs to Michael's children."

The foundation's director, Melissa Johnson, claims the pop singer handed her control of Heal the World through intermediaries in 2005, when he was defending himself against child molestation accusations. Despite never having personally met the singer, Johnson's attorneys claim she has the right to manage the charity, use various trademarks and that the permission now comes from the Jackson family itself.

"Mrs. Jackson has been told that Ms. Johnson's foundation is Michael's but that is not the truth," Jackson's estate said in a statement. "The estate hopes Mrs. Jackson will eventually understand the true facts and cooperate with the estate executors in selecting worthy charities as Michael would have wished."

The singer's estate counters that even if Michael Jackson granted Johnson rights to the charity, which it denies, the estate has revoked the permission and Johnson should be barred from using rights it owns to Jackson's name and, likeness.

"People are saying I have been manipulated by Melissa Johnson and that we are exploiting my grandchildren because we joined Heal the World, all while the executors convince people they are only doing what Michael wanted or what is in my best interests by suing everyone who help (sic) us," states Katherine Jackson's declaration, which was offered as sworn testimony in the case. "Please do not believe them. It's not true."

Complicating Katherine Jackson's involvement with the foundation is her business relationship with Howard Mann, a businessman who obtained some of Jackson's recordings years ago. Mann, who is paying to defend Heal the World in court, is also being sued by the estate in a separate lawsuit that accuses him of infringing on estate copyrights.

The estate accused Mann of trying to secure Jackson copyrights for profit, which it said would deprive Jackson's children of money they are owed.

The estate won a preliminary injunction in April 2010, barring Heal the World Foundation from using Michael Jackson's name, likeness and trademarks on its website, but in recent weeks several of the pop singer's former confidantes and his mother have cast their support with Johnson.

In recent months, several former Jackson insiders have signed statements saying they were aware Michael Jackson had given Johnson authority to run his charity. Among those expected to testify are attorney Brian Oxman, who was fired from Jackson's criminal defense team and now represents Jackson family patriarch Joe Jackson, and the singer's former manager and spokeswoman Raymone Bain.

In written testimony, Oxman and Bain both said they were aware Michael Jackson handed Johnson the reigns to the foundation in 2005. Estate attorneys have cast doubt on Oxman's testimony, noting his name was never mentioned in years of correspondence from Johnson to Jackson's attorneys and representatives.

Johnson's attorney, Edgar Pease III, admits that there is no formal written agreement between Michael Jackson and Johnson regarding Heal the World. But he says the involvement of Jackson's mother and three children, who are entitled to 80 percent of the estate's earnings, means the foundation should have some legitimacy.

"The estate is suing their left foot," Pease said. "They're suing themselves."

He said Johnson's aim in applying for various trademarks was to preserve them for the charity and protect them from profiteers. Tax records show in recent years, Johnson has not received a salary for her work on Heal the World Foundation, and in court filings claims she has spent tens of thousands of her own money to develop it.

Since Jackson's June 2009 death, there at times has been an uneasy relationship between the Jackson family and the estate. Michael Jackson's 2002 will calls for his mother and three children to receive 80 percent of his estate, with the final 20 percent designated for an unnamed charity.

Katherine Jackson had sought to challenge attorney John Branca and co-administrator John McClain's authority to run the estate in 2009, but dropped the bid.

In the meantime the estate has worked to repair major financial damage incurred by Michael Jackson during his lifetime. The "Thriller" singer died more than $400 million in debt, but in the first 17 months after his death earned more than $310 million, court records show.

More than $9 million has been paid to and for Katherine Jackson and her son's children, nearly $4 million of which went to pay off the family's longtime home.

For its part, Johnson's Heal the World Foundation spending of $76,000 in 2009 has far outpaced its donations, which totaled roughly $5,000.

In court filings, Johnson states she registered 1,800 website domain names and dozens of trademarks, which Pease said would give the foundation the basis it needs to fulfill Johnson's vision for the charity.

Pease claims Johnson came up with the idea for a Cirque-du-Soleil-style show featuring Jackson's work, as well as a telethon, television show, board game and other merchandise that would elevate Heal the World to a major charitable organization.

Jackson's estate is hoping next week's trial before U.S. District Court Judge Dolly Gee will end Johnson's efforts.