Autumn Pasquale: Authorities say two teen brothers arrested, charged with murder in NJ girl's slaying

(CBS) NEW YORK --  Authorities say two teenage brothers have been arrested and charged with first-degree murder in the slaying of 12-year-old New Jersey girl Autumn Pasquale, who disappeared Saturday while riding her bike around her neighborhood.

PICTURES: Body of missing NJ girl found

At a press conference Tuesday afternoon, Gloucester County Prosecutor Sean Dalton said Autumn died of blunt force trauma in a manner consistent with strangulation. He said the death had been ruled a homicide and that there were no signs of sexual assault.

The brothers,  ages 15 and 17, were each charged with first-degree murder, conspiracy to commit murder, tampering with evidence, disposing of a body. Police said the brothers turned themselves in to authorities on Tueday.

Dalton said the boys' mother contacted authorities about a posting on one of her sons' Facebook account, which helped lead police to the boys. After obtaining a search warrant, police found personal belongings at the brothers' residence, including Autumn's white BMX bike, which she had been seen riding before her disappearance.

Autumn was last seen around 12:30 p.m. Saturday, riding her bike away from her house, authorities said. Her body was found around 10 p.m. Monday evening in recycling bin near her home.

Complete coverage of Autumn Pasquale on Crimesider