A Springfield fire captain was injured as he helped battle a north-end fire that displaced a family of four.

Fire Chief Ken Fustin says crews got to the house in the 1400 block of Pennsylvania Ave. shortly after 11:00 Tuesday night to find fire showing in two rooms with heavy smoke throughout. The fire was under control in about 20 minutes. No one was home at the time.

The capitain twisted his knee and is expected to be okay.

Authorities think the fire is suspicious; it’s still under investigation.