Fire crews responded around midnight as flames came from the building. The blaze was escalated to a two-alarm response, and firefighters rescued one person from a second-floor balcony, officials said.

Plano fire officials suspect arson. Police took a person of interest into custody, but officials have not announced an arrest or charges. The fire department’s arson investigators are leading the inquiry.

The number of residents affected was not immediately clear. Property management and the Red Cross were at the complex to assist people displaced by the fire.