A gunman killed two people and wounded four others, including three police officers, before taking his own life in a home in the Dallas-Fort Worth area, police said Sunday.

Haltom City Police Det. Matt Spillane said none of those wounded in the shooting Saturday evening in a residential neighborhood have life-threatening injuries.

Spillane said the officers returned fire after being shot at while responding to a report of gunshots at the home around 6:45 p.m.

One officer was hit in both legs, and the other two were shot in the arm. The suspect died of an apparent self-inflicted gunshot wound.

He said the Texas Rangers – the state’s elite police force – would take over the investigation. A motive for the shooting was not immediately clear. Authorities have not released the names of any of the people involved in the attack.

"The main focus is on how and why this happened,” Spillane told The Associated Press (AP).

A woman was found dead inside a house and a man was found dead outside, Sgt. Rick Alexander said, speaking at a news conference late Saturday. A woman who called 911 was also wounded, he said.

The suspect was found with a "military-style rifle” and a handgun, Alexander said.

The incident is one of several in recent days in which law enforcement officers were fired upon while responding to calls.

Three officers were shot dead in eastern Kentucky while trying to serve a warrant. Police took a 49-year-old man into custody late Thursday night after an hours-long standoff at a home in Allen, a small town in the hills of Appalachia. He remains jailed on a $10 million bond charged with two counts of murder of a police officer.

In Chicago, a police officer was hospitalized in serious condition after being shot repeatedly in a Friday morning ambush while answering a domestic disturbance report, police Superintendent David Brown said. A suspect was hospitalized awaiting a psychiatric evaluation and is being held on a $2 million bond./AP