CHESTER, PA (CBS/KYW) -- A savage beating by girls who apparently thought it would be a fun idea to attack a mentally challenged woman is posted on Facebook. Now the girls are being charged as adults.

The girls can be heard laughing and celebrating as they took turns punching kicking and throwing a chair at a 48-year-old woman who was just sitting in her front step.

The melee continues inside her apartment and at one point you can hear the woman scream get off me

Joseph Bail says, "One of the most horrific attacks I've ever seen." Chester police commissioner Joseph Bail says the 6 high school aged girls seen in the video will be charged as adults.

Throughout the video you can clearly see many of their faces as they make no attempt to hide from the camera.

The attack happened here at this apartment at Morton Avenue and Johnson streets. The 48-year-old's neighbor Leonard Worby says he saw her after the attack. "Her face was all puffy all over the place, her face had cuts and bruises."

A surveillance camera from a store also captured part of the beating. The 48-year-old woman who we are not identifying lives alone, and could often be scene sitting on her front step. Bail says, "According to the interview with the victim, prior to when this assault occurred, she actually gave these girls some candy or bubble gum."

Police believe the attack happened possibly Tuesday night just after 9 p.m. The victim didn't contact police it's believed due to her diminished mental capacity.

It wasn't until Thursday morning when a resident tipped off Chester police. That authorities knew about the video that has stunned neighbors.

Neighbor Chris Naysmith says, "I felt sick to my stomach that someone could treat a person this way."

The woman was not seriously injured. As for the girls in police custody, they are scheduled to be arraigned tomorrow morning on felony aggravated assault charges.