"This appears to be a domestic incident and the victims were all known to our suspect", Chacon told reporters on Sunday afternoon. "At this point, we do not think this individual is out there targeting random people to shoot".
Three adults were pronounced dead on scene, according to Austin-Travis County EMS. A child linked to this incident is safe, Chacon said.
Travis County District Attorney Jose Garza said in a statement that Broderick had been arrested for sexual assault of a child last June and was released on $50,000 bond.
Authorities said they do not know the direction Broderick headed or whether he is in a vehicle or on foot. Broderick resigned from the department after his arrest a year ago, according to the report.
When officials arrived on scene, two women and a man were found shot to death outside an apartment building.
Broderick's wife filed for divorce and a protective order after his arrest, the Statesman first reported, citing court documents. Later Sunday, law enforcement began leaving the area. The area where officers responded includes a strip mall and several retail stores with a large apartment complex behind it. On Sunday, police swarmed the area searching for 41-year-old Stephen Broderick, who is considered armed and risky.