The 15-year-old girl savagely beaten by group of teen girls in a horrifying viral video shared in Chicago had been missing for five days and may have been sexually assaulted, police said Wednesday.

Officer Jose Jara said detectives are trying to piece together basic information, including where and when the attack caught on video occurred as he revealed the victim was not reported missing for nearly a week.

Jara said the girl indicted that she had been sexually assaulted and that she was treated at a hospital and released.

The police unit that investigates sex crimes has been called in.

Chicago police say a 15-year-old girl whose attack by a group of young people was captured on cellphone video and shared online may also have been sexually assaulted off camera at some other point. The girl was treated at a hospital and released, police say

The shocking video posted online shows several young women beating the teen as onlookers laugh.

It was posted online by a person who wrote she was a friend of the victim, whom she described as having a 'mental disability.'

It was originally claimed that the girl was assaulted when she asked the group for assistance to help her get to the closest Red Line train station.

The friend, who posted the footage online, said that the teenager has a mental disability that developed after the death of her mother.

Footage shows the group attack the girl, who screams as she is punched in the face.

She tries to defend herself but is bombarded by punches.

The teens can be heard shouting about how the girl was allegedly going to call the cops on them, throwing her to the ground as they continue their onslaught.

The horrifying clip has been viewed more than 4.5million times.

Officer Jose Jara, a police spokesman, said Wednesday that detectives are trying to piece together basic information, including where and when the attack caught on video occurred

It was also seen by Officer Anthony Guglielmi, the chief communications officer for the Chicago Police Department, who confirmed that the Special Victims unit was investigating the video.

'This is beyond disturbing to watch and this young girl deserves far better,' he said in the tweet.

Friends and concerned folk were curious of the girl's whereabouts following the attack. A brief video appeared to show the teen on a Blue Line, and it was shared that she was safe with family.

Several users also shared post said to be of the girls who took part in the beating.

They shared that they have been receiving threats from the video going viral and apologized for attacking Harris.

Various users rushed to identify the group and shared their information on social media.