A woman is in hospital and a man in custody after she fell from a downtown apartment balcony early Friday morning.

Police said the woman fell three storeys from an apartment on Sherbourne Street near Dundas Street East at about 1:30 a.m.

The semi-conscious woman was taken to a downtown hospital with serious but non-life threatening injuries.

Police are not saying much about the incident, however, CP24 reported that the woman fell while police were trying to resolve a domestic dispute.

A man, wearing only his underwear, was taken into custody.

Ontario's Special Investigations Unit has been called in to investigate.

The SIU is called when there has been death, serious injury or allegations of sexual assault involving the police.