The RCMP missed crucial evidence in its review of a bungled 911 call that left a victim clinging to life for four days before she died, according to documents obtained by CTV News.

Despite two successive internal reviews by the Mounties, it was civilian investigators from Alberta that discovered an audio recording that shows then-Const. Mike White laughing dismissively before he was dispatched to a shots fired call in Mission, B.C. in 2008.

"Both investigators of the internal reviews acknowledge that they were not aware of the existence of this phone call and had not heard the recording during their investigation," wrote the report by the Alberta Serious Incident Response Team, which was signed off by director Clifton Purvis.

The evidence was one of several concerns pointed out by ASIRT about the incident, where Lisa Dudley and her boyfriend Guthrie McKay were shot inside their Mission Home in September, 2008.

Constable Mike White responded to the 911 call that night. He never left his car, turned away support from a fellow officer, and never talked to the 911 caller, according to the ASIRT report.

Four days later, a neighbour found McKay dead -- but Dudley was clinging to life. She died en route to the hospital. Dudley's parents say if White had left his car and talked to the caller, he would have had a chance to find her and save her life.

"I believe that they would have found the murder scene and helped her out. For someone to live four days, paralyzed, is most uncomfortable to think about," said Dudley's stepfather, Mark Surakka.

In the call between White and the radio dispatcher as he is en route to the call, White says "Six gunshots in a row and shots," and then chuckles. The dispatcher responds, saying, "yeah, exactly." White chuckles again. The dispatcher says, "Don't you love this?" White replies, "Yeah, I'll head out," and the call is disconnected.

Both RCMP administrative review and its investigation in response to the Surakka's complaint neglected to find the audio recording.

But when the recording was made available to the Commission for Public Complaints against the RCMP, interim chair Ian McPhail says the call was proof White never intended to take the 911 call seriously.

"Corporal White's dismissive comments and tone serve to further demonstrate that he had predetermined there was no validity to the complaint of shots fired," wrote McPhail. "This explains his lack of investigation and the results that followed."

Surakka said they haven't heard the call, but his wife Rosemary burst into tears when she saw the call transcript.

"911 is a lifeline," he said. "It was Lisa's lifeline, and it was neglected."

Rosemary Surakka said she has not yet recovered from the pain of losing her daughter.

"My heart isn't broken, it's shredded into pieces," she said.

ASIRT is a civilian investigation unit in Alberta whose mandate is to investigate death or serious injury involving a police officer. They are led by Clifton Purvis, who is a lawyer and crown prosecutor.

The ASIRT report -- which the RCMP asked for in anticipation of a lawsuit from the Surakkas -- also takes issue with the RCMP's description of White's actions on the scene.

The RCMP report from April 22, 2009 says that White attended the scene from 11:02 to 11:14, or 12 full minutes.

But the ASIRT examination of GPS data from White's car shows that he did arrive at 11:02 -- and then cleared the file at 11:07, five minutes later. He sat in his car from 11:07 to 11:15 -- seven full minutes -- before he was reassigned to another call.

The RCMP didn't respond to calls for comment today. But RCMP Insp. Tim Shields told reporters Friday that White had been given a letter of reprimand and docked a day's pay.

Shields added the force had made changes since the case was reviewed.

"From this point on, any shots fired complaints have to be investigated in a much more thorough manner, which includes direct contact between the investigating officer," he said.

The ASIRT report says a requirement for an officer to contact a complainant during an investigation may not be in the regulations -- but officers had to contact complainants after they concluded the file at the time of the Mission incident.

The ASIRT report concluded that White had failed to contact the complainant. But it stopped short of saying that the RCMP's own investigation was not thorough.

The Surakkas say the omission of the call and the GPS data is proof the RCMP should not investigate itself. Mark Surakka said that if B.C. had its own civilian police oversight, they would have had answers sooner, without constantly pressuring the police for more.

"They leave you twisting in the wind," he said.

B.C. Solicitor-General Shirley Bond sent CTV News an e-mailed statement where she agreed that an independent investigation oversight office should investigate deaths and serious injuries involving police.

But she said more study was required before it could be implemented.

With a report from CTV British Columbia's Jon Woodward