A troubled husband and father opened fire at his son's birthday party at a Texas roller rink, killing his wife and four of her family members before taking his own life.

Tan Do, 35, and his estranged wife, Trini Do, 29, were hosting their son's 11th birthday party at Forum Roller World in North Texas when an argument erupted.

After ordering the children to flee, Tan Do pulled a gun and fatally shot his wife, her two sisters, Lynn Ta, 16, and Michelle Ta, 28; her brother, Hien Ta, 21; and her sister-in-law, Thuy Nguyen, 25. He then put his gun on himself and took his own life.

Their son and his sibling left the rink before the shooting and are unharmed. Both children are staying with relatives (it is not known if the relatives are on their father's or mother's side of the family).

The couple had been having an ongoing domestic dispute, with disagreements going on for some time, Grand Prairie Police Department spokesman John Brimmer said.

They were estranged. They'd been having some marital problems, he said.

This was a domestic situation that went south in a hurry, Brimmer added. The shooting lasted only seconds.

The dad got distraught. And just out of nowhere, bang, bang, bang! It was just so quick and everything. There was nothing that could be done. It looked like he knew who he was looking for to shoot, Walt Hedrick, owner of the roller rink, told NBC.

I'm sorry that something like this had to happen anywhere. The families and friends of all the people that are not with us anymore. My prayers are with them.

Hedrick said he normally hires security when the rink is open to the public, but declined to do so for this small private party of about 30 guests.

Forum Roller World is in Grand Prarie, about 20 miles from Dallas.

[Sources: Reuters, msnbc.com]