Fayetteville, N.C. — Fayetteville police are investigating why officers weren't dispatched for more than an hour last Monday after a 911 call was received from a home where a family of four was killed in a murder-suicide.

When the 911 operator answered the first call, at 6:38 p.m. Nov. 2, no one responded. The sounds of someone in distress and what could be a gunshot were audible in a recording of the call released last week.

The call was cut off, and the operator tried to redial the number but got a busy signal, according to the recording.

A second 911 call was made at at 8:01 p.m. Nov. 2, when a man tells a dispatcher that he went over to his daughter's home and could see bodies inside.

Police said William "Billy" Maxwell Jr., 47, killed his family at 314 West Park Drive. The victims included his wife, Kathryn Maxwell, 43, daughter Connor Maxwell, 17, and son Cameron Maxwell, 15.

Billy Maxwell was suffering from mental illness, the Rev. John Cook, pastor of Snyder Memorial Baptist Church, told mourners at the family's funeral service on Friday.

Fayetteville Police Department spokeswoman Theresa Chance confirmed Monday that the first call came from a home phone inside the Maxwell house and not a cell phone. She said officers called back a second time and left a message on the home answering machine.

Police Chief Tom Bergamine said the response time to the first 911 call is under internal review.

The department has an enhanced 911 system that allows dispatchers to pinpoint the location of calls made from landline phones when there's no response.

"Hopefully, we'll be getting this done and taken care of very quickly," Bergamine said.

He declined to discuss details of the investigation.

The first call is what police describe as an abandoned 911 call. The police department's 911 call center has received about 46,000 such calls this year, Chance said.

“The protocol is, the first thing they do is check for a call history to see if there is some evidence of medical issues there or maybe domestic (violence calls). The second thing to do is a callback to the residence,” said Capt. Brad Chandler, commander of the 911 center. "(An abandoned call) is put into the system, and it's a Priority 4, which gives us 20 minutes to dispatch or notify somebody."