Two men died Saturday night in a two-alarm fire at 716 Willow Ave. that authorities were calling suspicious.
The victims were not identified as of early this morning, but fire officials said one man appeared to be in his late 20s. The other man was older, according to Battalion Chief Frank Eugeni.
No other injuries were reported.
The exact cause of the fire is not known, but Eugeni said someone is believed to have thrown a Molotov cocktail into the building.
Officials said a man who lives on the second floor of the three-story building heard a window shatter on the first floor, then saw flames.
The man ran upstairs to warn other residents, witnesses said.
The fire started in the seven-unit building about 7:45 p.m. and was brought under control by 10:30 p.m. Firefighters still were on the scene early this morning.
The fire is believed to have begun in a living room area on the first floor. Authorities said the victims were found on the second floor.
The building, a partly brick structure at the corner of Willow and Whirlpool avenues, was declared a total loss.
Fire officials said they do not know if the building had smoke detectors.