An arson fire near tennis courts at the Park Place Apartments Monday night spread to one building, and burned outdoor window coverings, an official said.
No one was injured in the fire, which was reported by 911 callers at 8:23 p.m., said Capt. Adam Goldberg of Northwest Fire District.
Twenty-one firefighters arrived in four minutes and fought the blaze at the complex, 11 E. Orange Grove Road, bringing it under control in 19 minutes, Goldberg said.
Witnesses told investigators that the fire was "intentionally set", said Goldberg. He did not release further information about the arson.
A damage estimate was unknown, Goldberg said.
Pima County Sheriff's Department detectives were conducting an investigation, said Goldberg.
Goldberg said the fire was burning dead vegetation and vines covering a chain-link fence near the tennis courts, and spread and burned window coverings on one apartment building.
The building had four apartments, and firefighters only needed to evacuate two apartments because the other two were already empty, said Goldberg.
The blaze also burned two eucalyptus trees and three palm trees, Goldberg said.