Missing Girl Cold Case Solved After 25 Years? Mom Says No Police closed the case without charges: brother confessed to accidental killing.

ST. AUGUSTINE, Fla., Jan. 2, 2010  -- Authorities in northeast Florida say they've closed the 24-year-old case of a missing seventh-grader, but the girl's mother says she doesn't believe it.

Martha Jean Lambert vanished near her St. Augustine home on Nov. 27, 1985. Her mother, Margaret Pichon, says she remains convinced that the 12-year-old girl was kidnapped.

However, the St. Johns County Sheriff's Office said Friday that Pichon's son David Lambert has confessed to accidentally killing his sister in an argument.

Sgt. Chuck Mulligan said Lambert told police that he panicked and buried the girl in a shallow grave. Lambert was 15 at the time.

The State Attorney's Office decided not charge Lambert with manslaughter after prosecutors considered his age at the time, the statute of limitations manslaughter charges had in 1985 and "other mitigating circumstances," Mulligan said.

Investigators had considered Lambert a suspect, but they had no evidence nor a confession until sheriff's detectives Sean Tice and Howard Cole III reopened the case in June.

Lambert, now 38, had previously told investigators that he last saw his sister as she walked off to play.

When Tice and Cole interviewed him again last summer, Lambert told them he and Martha Jean were arguing near the old Florida Memorial College site over $20 he refused to give her, the detectives said. The girl punched him in the face, and Lambert said he shoved her backward. Her head landed on a piece of metal sticking out of the ground, he told the detectives.

"D. Lambert stated when he lifted Martha up there was a large hole in the back of her head and blood was pouring out," Tice wrote in the offense report. "D. Lambert stated he initially called out for help, hoping that someone would be walking by and hear his cries."

Lambert told the detectives that he dug a hole 3 feet deep and laid Martha Jean in it.

"He was terrified," Tice told The St. Augustine Record. "He was terrified of his Mama. Still is."

Pichon says the sheriff's office just wants the case closed. Authorities still haven't found her daughter's remains, though crews searched the site Lambert indicated in his recent interviews.

Demolition at the site over the past 24 years "is believed to have removed or scattered any remains that may have existed," sheriff's officials said.

Pichon told The Florida Times-Union that Lambert "makes up tales" to get attention.

Mulligan said investigators believe Lambert is telling the truth.

"We certainly understand the complexity and the difficulties these situations bring on a family," Mulligan said. "These are his words."

Martha Jean's disappearance was the county's longest-running missing person investigation.