It's not clear what sparked a massive fire that gutted two houses in Queens on Thanksgiving Day.

It started just after 6 p.m. inside 162-11 108th Avenue in Jamaica.

Nobody was home at the time.

Investigators believe the cause is suspicious, since the fire was so intense.

The members did an outstanding job getting lines in...from extending down the row of houses."

One firefighter was injured. 

The Red Cross is helping nine people who were displaced by the fire.