TWO men were fatally stabbed in self-defence by a terrified teen after a drunken lovers' tiff, quad bike accident and violent home invasion on a booze-filled NRL grand final night, police say.

News Queensland can today reveal the tragic set of events that led to father-of-three Corey Christensen, 37, and Tom Davy, 27, being stabbed to death outside a home in Alva Beach, near Townsville.

Police are investigating if resident Dean Webber, 19, acted in self-defence as the two men barged into the house trying to calm a distraught, injured Candice Locke, 29 shortly after midnight on Monday.

The former Townsville RSPCA worker from Ayr broke her shoulder after falling off a quad bike on the beach and had run off down the street in a distressed state looking for somewhere to call an ambulance.

Ms Locke's long-distance boyfriend of three months, Mr Davy, and local man Mr Christensen - who they'd met just hours earlier at an ­alcohol-fuelled grand final after-party - had followed her, trying to calm her down.

It is understood the two lovers had argued earlier in the evening about going home before partying at the vacant block beside the Ayr Surf Club with dozens of locals and residents of the tiny fishing hamlet.

Some time later Ms Locke, who had been drinking, fell off a quad bike on the beach, badly dislocating her shoulder.

It is understood Ms Locke was urged by others not to call for help because of fears that someone would be charged with drink-driving.

Ms Locke, in pain and crying for help, banged on the door of local apprentice fitter Mr Webber, who was home alone house-sitting at the family beach house after a series of recent break-ins.

Mr Webber let her in and called an ambulance, but moments later the two men turned up at his front door.

It is believed the two men, both older and bigger than the thinly built teen, had torn open the screen door.

Mr Webber, who had also been drinking while watching the grand final, is believed to have grabbed a knife to protect himself and Ms Locke.

In the ensuing chaos, both men suffered critical stab wounds and Mr Webber was slashed on his leg by the knife.

Police and paramedics turned up to find Mr Davy and Mr Christensen lying in pools of blood on the road outside the Topton St home.

Two police from Ayr station, 15km away, have told fellow officers of their horror as they performed CPR trying to save one of the men.

Mr Christensen's wife, Jaye Christensen, yesterday called for answers, saying the family was unable to comprehend what had happened.

"I have lost my husband and best friend and our three sons have lost their daddy," she said.

"Anybody who knew Corey loved him, our boys are so lucky to have the most amazing dad anybody could wish for."

Former RSPCA Townsville worker Ms Locke has been "inconsolable" and "deeply distressed" as she recovers in hospital from surgery to her busted shoulder.

Lead investigator Detective Inspector Chris Lawson said it was an "extraordinary set of circumstances" that ended in tragedy.

"It's a case of the kind I've never come across before, and hopefully will never deal with again,'' he said.

"We still have to sit down and go through all the evidence and make sure all the evidence is lined up, before we make a decision either way.

"But it's likely no criminal charges will be laid and this will end up in the Coroner's court."

Acting Senior Sergeant Craig Hosie, the officer-in-charge of Ayr police station, said: "We've got four families whose lives have been turned totally inside out''.

"There were a number of factors that lined up, and built into a perfect storm," Sen-Sgt Hosie said.

"There is no evidence it was drug related, the only thing muddying the water is that a lot of alcohol had been consumed that afternoon and into the night.

"This has saddened a big part of the community, and it has had a devastating effect on people who are well known and highly regarded across the Burdekin district.

"Corey's wife Jaye now doesn't have a husband, she now faces life as a single mum, bringing up her three little boys alone, who are asking "Where's Daddy?, Where's Dad?"