London, April 1 (Inditop.com) A 15-year-old American girl was arrested after allegedly selling her seven-year-old stepsister to a group of men for sex at a party.

The teenager took her sister to an apartment close to their home in Trenton where the younger girl was raped by about seven men, New Jersey police said.

The older girl was believed to have been present during the rapes and was paid by those who took part. She has been charged with aggravated sexual assault, promoting prostitution and other crimes, telegraph.co.uk reported.

‘We’re talking about a kid who told her sister to go into an apartment and let people rape her,’ said Trenton police Captain Joseph Juniak. ‘It’s unfathomable.’

The older girl, whose identity was not revealed because of her age, is being held at a youth detention centre.

The younger girl had wanted to accompany her sister to the party because she was worried about her safety, Mayor Doug Palmer said.

Their parents called police when the girls didn’t return home by 4:30 p.m. Sunday.

The seven-year-old narrated the incident after police found both outside the apartment.

When they reached the apartment, the teenager encouraged her young sister to let the men touch her.

‘It went from touching to straight out assault and rape. They threatened to kill her if she screamed or told anyone,’ Captain Joseph Juniak was quoted as saying.