Follow CBSDFW.COM: Facebook | Twitter

DALLAS (CBS11 I-TEAM) – After Monday’s shooting of Dallas Fire-Rescue paramedic William An, several Dallas firefighters have told the CBS 11 I-Team they’re frustrated with the slow response times by the Dallas Police Department.

Firefighters said it is routine for them to arrive to a scene of a shooting before police as was the case Monday.

However, Dallas police officers arrived at the gunman’s home in the 3200 block of Reynolds Avenue just six minutes after being dispatched.

Plus, no one knew at the time of dispatch that it was active shooter situation.

Police say the originally 911 call came in as a possible suicide. Investigators would not say who placed that call.

Before the 911 call was made, investigators say Derick Brown shot and killed his godfather, 66-year-old Arthur Riggins, in the back bedroom of their home.

Riggins’ girlfriend ran out of the home for help.

Brown also came outside where he shot a neighbor and firefighter-paramedic An, who had come to the aid of the neighbor.

When police officers arrived, they managed to pull An and the injured neighbor to safety.

An, 36, is in critical but stable condition at Baylor Medical Center in downtown Dallas.

During the shootout with police, Brown was shot by an officer and retreated into his home.

SWAT eventually sent a robot into the home where Brown along with Riggins were found dead.

Police say it appears Brown died from a self-inflicted gunshot wound.