After sharing that detail of Thursday night's attack with area clinics, police received a call from a medical center when a man arrived Friday morning for treatment of an injured tongue.
The unidentified man fled when police came for him, but he was later caught. He was being questioned Friday.
Stamford Police Capt. Richard Conklin said the woman was attacked late Thursday in an alley near a church and that officers recovered "a substantial piece" of the assailant's tongue at the attack scene.
The victim was treated Thursday night at Stamford Hospital.
No arrests were immediately announced Friday.