(Photo credit: Martin County Sheriff's Office/John Milano)

The mystery of a missing $350,000 diamond ring in Florida has been solved. A house cleaner has been arrested and charged with grand theft after she allegedly sold the ring to a pawn shop for $4,800. She told police she needed the money to feed her children.

Cody Mejias, 26, was an employee of a cleaning service that cleaned the Stuart, Fla., home of Robert Hill and his wife on Dec. 21. The ring disappeared from the house and the couple were convinced that it was stolen and not lost, so they hired top Florida private investigator John Milano.

Milano said it was a failed polygraph test that led him to Mejias.

"It came from the polygraphs. She failed the previous Saturday," Milano said. "She was avoiding me. I hunted her down. She refused to come in so we had to get police involved."

The ring was traced to Jensen Beach Jewelers and shop owner Charles Sarullo. Mejias had sold him the ring for $4,800. Milano called Sarullo and offered him the $5,000 reward the Hill couple were offering as well as the $4,800 he had paid for the ring if he would return it. Sarullo said no.

"According to Sarullo, Mejias came in on 12/22/11 and stated she received a diamond ring as an inheritance from a recently deceased aunt," the Martin County arrest affidavit for Mejias said.

The ring was seized and Mejias was arrested. When shown the ring, she confirmed that she had stolen it while cleaning the Hill residence, according to the affidavit.

"Mejias was apologetic and stated she needed the money to feed her children," the police document said. "Mejias advised the money she retrieved from the transaction was used for food, gas, Christmas gifts and bills."

Mejias also wrote the ring's owner an apology letter. She is being held on a $20,000 bond.

The sparkler is very unusual and Milano said it would have been extremely difficult to sell it and go undetected.

"The main stone is an oddity, a 10.38-carat emerald-cut diamond," Milano said. "The side diamonds are also one carat each and kite-shaped, which is an unusual cut."

Milano said the couple are just glad to be getting their ring back.

"They're extremely excited. They're ecstatic," he said. "This is not the route we wanted to take, but we're very happy it got resolved."