Police in New Jersey's capital city say a 15-year-old sold her 7-year-old sister to have sex with as many as seven men and boys at a weekend party near their home.

Trenton police said Wednesday the child later put on her clothes and two strangers walked the crying girl home. She was treated at a hospital.

Police say the teenager, who stayed behind, also took money to have sex with others at the party in an apartment Sunday.

The older girl is charged with aggravated sexual assault, promoting prostitution and other crimes. Her name was not released because of her age.

Police are trying to track down the men and boys who attended the party.

The girls' parents reported them missing Sunday afternoon and police were at the home when the 7-year-old returned.