A woman is in critical condition after falling from the seventh floor of an apartment during an arrest by Toronto Police.

The incident occurred around 11:30 p.m. Sunday during a police sweep for trespassers in the building, on Lansdowne Avenue near Dupont Street.

The officers confronted a man and a woman in an apartment, and were in the process of arresting the man when the woman fell from a window.

The 26-year-old woman was taken to St. Michael's Hospital with serious injuries.

The man briefly escaped police custody but was re-arrested a short time later.

The case is now being investigated by the province's Special Investigations Unit, a civilian agency that investigates circumstances involving police and civilians which have resulted in serious injury, death or allegations of sexual assault.

SIU spokesperson Rose Bliss said one police officer has been named as the subject of the investigation, and three more officers have been identified as witnesses.