The ex-husband of Melissa Huckaby — the suspected killer of 8-year-old Tracy girl Sandra Cantu — was on Monday granted sole custody of the couple’s daughter, court records show.

Johnny Huckaby reached a settlement with his former mother-in-law, Judy Lawless, which allows her to visit 5-year-old Madison Huckaby as long as the little girl has no contact with her mother, according to papers filed in Orange County Superior Court.

Melissa Huckaby has been held in solitary confinement in the San Joaquin County Jail since her April 10 arrest. Johnny Huckaby lives in Arkansas and Lawlesses in the Southern California city of Cypress.

A hearing brief filed Monday by Johnny Huckaby’s attorney says Madison has been “flourishing” under her father’s care. The couple married in 2004 and divorced in 2005.

The brief says Judy Lawless has been unable to prove that it would be detrimental to the girl’s well-being to be in her father’s custody.

“Madison has been doing exceptionally well in her father’s custody,” wrote Johnny Huckaby’s attorney, Ann Thompson, in the brief.

The week after Tracy police arrested Melissa Huckaby on suspicion of kidnapping, raping and killing Sandra, her ex-husband asked a judge to grant him custody of his daughter.

He included in his petition a copy of the criminal charges against Melissa Huckaby and accused her of having tried to commit suicide by swallowing razor blades.

Madison used to play with Sandra, her mother told the Tracy Press the day of her arrest. Madison was living with her mom and great-grandparents in Orchard Estates Mobile Home Park, where Sandra also lived, before her mother was jailed. After Melissa Huckaby’s arrest, Madison’s grandparents, Judy and Brian Lawless, took the girl to live with them in Cypress, according to court papers.

A judge in April granted Johnny Huckaby temporary custody of his daughter. Judy Lawless then asked the court to reconsider and allow her to keep the girl. She argued that Johnny Huckaby was an estranged father and lived 1,700 miles away for much of Madison’s life.

Johnny Huckaby in turn accused Judy Lawless of lying about Madison’s whereabouts to keep her from him. The court sided with him and Madison now lives in Arkansas with a step-brother, half-sister and a step-mom.

Prosecutors accuse Melissa Huckaby of murder with special circumstances of rape by instrument and kidnapping. They added charges that she drugged a 7-year-old girl in January and a 36-year-old Hayward man in March.

Sandra went missing on March 27. After a widespread search, farmworkers on April 6 found her lifeless body in a black suitcase. Police arrested Melissa Huckaby four days later.

The Stockton Record reported last week that prosecutors will take the case to a grand jury, which will reportedly convene on July 20.

•Contact Tracy Press reporter Jennifer Wadsworth at 830-4225 or jwadsworth@tracypress.com.