With his two youngest children cowering in the corner of a bedroom, Hien Tuan Lam killed his wife and shot his 15-year-old daughter in the face after feeling disrespected by them during a fight.

Those are some of the facts read aloud in court as Lam, 44, pleaded guilty to second-degree murder and discharging a firearm to endanger a life.

On May 24, 2016, Hue Ngoc Nguyen, 41, died in the bedroom she'd been sharing with her three children — ages 15, 11 and three at the time — since fights with her husband of 18 years had escalated in the month before the shooting.

Lam was originally charged with first-degree murder and attempted murder.

Much of the information contained in the agreed statement of facts drafted by Crown prosecutor Shane Parker and defence lawyer Gavin Wolch comes from the middle child, who witnessed the shooting.

Hien Tuan Lam told Justice David Gates he wants to eventually make contact with his children. (CBC)

Between 11:00 p.m. and midnight, Lam got angry and called his wife a prostitute when she told him she wanted to start working again.

Nguyen went into her kids' bedroom and closed the door but her husband returned a minute later, threatening to "blow open the door."

Shortly after, he returned with a pistol.

The 15-year-old, who has since recovered from the shooting, called 911.

Teenager plays dead

The 11-year-old sister huddled in a corner of the room with her three-year-old brother and watched as her mother and sister were shot in the struggle.

The teen played dead as her father shot her mother a second time, after saying she "deserved to die."

Lam told his youngest children to get their jackets but at the front door, said he'd forgotten something and went back into the bedroom. The children heard another gunshot.

The fatal shooting took place in the family's home on Rundlehorn Drive. (Dave Gilson/CBC)

Meanwhile the 11-year-old was stalling in hopes help would arrive before she and her brother were forced to leave with their dad.

Lam drove to his sister's house, giving each of the children keepsakes along the way with the belief he would be going to jail for a long time.

Lam chatted with his sister and then drove off with the kids.

Nguyen died in a pile of laundry

Lam shot out of his window while driving.

Officers, who were already looking for his vehicle, witnessed the shot, pulled the car over and were able to get the two children to safety and arrest Lam.

Back at the family's home, the 15-year-old called 911 again. She was taken to hospital with two gunshot wounds to her face, two to her hands and one to her arm.

After falling into a pile of laundry, her mother, who had been shot in chest and head, died.

Lam's criminal record includes three convictions for aggravated assault in Yellowknife in 1994 and drug trafficking in Calgary in 2006. He was prohibited from owning a weapon at the time of the shooting.

When police searched the home after the shooting, they found Lam had a secret room full of rifles and ammunition.

'One of the saddest cases'

None of Lam's family members were in the gallery for his guilty plea.

Parker told the court he asked if the children wanted to write victim impact statements but they declined because they feel "caught in the middle."

Wolch said the night of the shooting, Lam made "the biggest mistake of his life" and is "terribly" remorseful.

"He relives this every day," said Wolch. "He accepts full responsibility ... he wants to better himself as best he can."

Lam hopes to see his children again one day, said Wolch.

Defence lawyer Gavin Wolch says his client relives his crime every day. (Meghan Grant/CBC )

Court of Queen's Bench Justice David Gates accepted the joint recommendation of a life sentence with no chance of parole for 12 years.

"This is one of the saddest cases I have ever come across in my time as a judge or my time as a lawyer," said Gates.

When Gates confirmed Lam had not seen or spoken to his children in nearly a year, he suggested writing them a letter.

"Mr. Lam, I would encourage you to not wait too long because my fear is that your youngest child ... with the passage of time, he may forget you, which I'm sure you don't want."

"I hope and pray [the children] receive the kind of love and support ... they may need so they may go on to put this terrible event behind them and go on to live a happy and productive life."

Lam's two daughters are set to receive an award for bravery from Calgary's police chief later this year.