NEW YORK (CBSNewYork) — One person was killed, and 12 more were injured, when an extra-alarm fire broke out Monday evening in an apartment building in Hamilton Heights.

The fire broke out around 5:45 p.m. in the six-story building at 512 W. 136th St., near Amsterdam Avenue and close to the City College campus, fire officials told CBS 2.

The fire was later raised to a third alarm, and fire officials have now deemed the blaze suspicious.

1 Dead In Hamilton Heights Apartment Building Fire

The FDNY told CBS 2’s Tracee Carrasco that one person was killed. The victim was found on an upper floor staircase landing and was so severely burned that it was not clear whether it was a man or a woman.

The victim had been trying to escape, the FDNY said.

“We don’t know what apartment the person came from other than they were found on the top floor and they were badly burned,” Nigro said.

Two other civilians were also injured, and one of them required hospitalization, fire officials said. A total of 10 firefighters were also injured.