The Texas shooting that left a paramedic critically injured and two others dead began as an argument between the suspect and the first shooting victim, who were neighbors, cops said late Monday.
In the tense moments following the initial shooting, an EMT who responded to the scene was critically injured when cops say the suspect opened fire on paramedics tending to the wounded neighbor.
The injured paramedic is out of surgery and remains in intensive care, but may have to undergo additional surgeries, authorities said.
The wounded neighbor is also in the ICU.
With the community on lockdown following the late morning shooting, police went door-to-door in search of the suspect.
The gunman, identified by WFAA as 36-year-old Derick Lamont Brown, holed himself up in a house where investigators believe he fatally shot a person before killing himself.
The two bodies were discovered by a police robot, authorities said early Monday evening.
Family members reportedly told the station Brown is the father of 18 children and worked as a janitor at an area hospital.
The victims have not yet been identified.