Aram Boghosian for The Boston Globe

Firefighters continued to work at the scene of a house fire on Arlington Street in Worcester.

Aram Boghosian for The Boston Globe

The three-alarm fire broke out about 4 a.m. at 49 Arlington St. The fire caused the building to collapse, killing one firefighter.

Aram Boghosian for The Boston Globe

Officials confirmed the death of the firefighter shortly after 7:30 a.m. today. Another firefighter was injured.

Aram Boghosian for The Boston Globe

The cause of the fire remains under investigation.

Aram Boghosian for The Boston Globe

This morning, Lieutenant Governor Timothy Murray, a Worcester resident and former mayor, stopped at the Arlington Street scene.