UNIVERSITY PARK (CBSDFW.COM) – A two-alarm fire caused “substantial damage” to a two-story duplex Monday after it spread to the attic before fire officials arrived.

University Park Fire Department Chief Randy Howell said two families who lived in the duplex in the 4400 block of Glenwick were displaced. The emergency call came in at 11:38 a.m. Monday, he added.

READ MORE: FDA Authorizes COVID-19 Booster Shots From Moderna, Johnson & Johnson

None of the residents were home when the fire began. Howell said the building’s owner lived on the first floor and rented the second floor out.

READ MORE: DFW Nonprofits To Start Holiday Drives Early Due To Supply Chain Concerns

Howell said the person who rented the room called police after she returned and found heavy smoke inside the building.

MORE NEWS: Arlington Police Officer Shoots, Kills Suspect Who Allegedly 'Drove Directly Towards Officer'

The chief did not know how the fire started nor a dollar amount of the damages.