A 13-year-old girl in Radnor Township is in police custody after arguing with another teen, then stabbing her at the residential treatment center where they both live Monday night.

The victim, another 13-year-old girl, was taken to Bryn Mawr Hospital in stable condition after being stabbed in the leg at about 7:30 p.m. at the Presbyterian Children's Village, police said.

Officials were unsure of what the two were arguing over, and were still investigating the incident and interviewing witnesses Monday night.