Two multifamily homes in Mount Vernon went up in flames Tuesday morning.

Authorities say the blaze broke out at 214 Union Ave. at around 6:30 a.m. and spread to the home next door because of strong winds.

Investigators say four families are now homeless because of the fire. A firefighter injured his ankle while battling the flames.

"We're not sure right now how we learned about the fire this morning," says Chief Al Everett, of the Mount Vernon Fire Department. "Not a lot of people on the street and the fire in the first building had a good head start."

Local residents say squatters have been seen in the house where the fire started. Both police detectives and arson investigators are trying to determine exactly how the fire started.

To watch footage of the fire that damaged two Mount Vernon homes, go to channel 612 on your iO digital cable box and select iO Extra.