MARTINEZ -- Prosecutors on Friday dropped charges against the mother of a teenager accused of killing a prominent attorney's wife after she agreed to testify against her son.

Esther Fielding, 53, was being held in lieu $500,000 bail on suspicion of being an accessory to murder. Her son, 16-year-old Scott Dyleski, faces a first-degree murder charge in the death of his neighbor, Pamela Vitale.

Fielding appeared Friday afternoon in court, where prosecutors said she helped Dyleski destroy evidence. But prosecutor Harold Jewett agreed not to press charges when Fielding said she was ready to testify truthfully.

Vitale was the wife of defense attorney and television commentator Daniel Horowitz. Her body was found Oct. 15 by Horowitz in a mobile home on the Lafayette hilltop estate where the couple were building their dream home.

That night, Dyleski called his mother, who told him to stay at his girlfriend's Walnut Creek house because police had blocked the road, according to an affidavit.

Investigators seized a duffel bag from a vehicle at Fielding's house that contained clothing and a glove, both with traces of blood, court documents said.