Police say investigators believe the deadly weekend attack at a Grand Prairie roller-skating rink was planned.
Six people were killed and four were wounded Saturday night when Tan Do, 35, opened fire with a .40-caliber pistol during his son's 11th birthday party at Forum Roller World.
Investigators said it seems that Do wanted his estranged wife's family in the same room at the same time.
Witnesses said Do's wife, 29-year-old Trini Do, and her family were sitting at a table in the snack area when her husband ordered the children to leave the room. He then started shooting shortly afterward.
Roller World owner Walt Hedrick, who took cover in his office along with his employees, said Do looked "deliberate" and "focused" as he shot his victims one by one. He then went back and shot them a second time before turning the gun on himself, he said.
Investigators said that going back to shoot the victims a second time shows that Do planned the attack and possibly targeted specific people.
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; were killed.
Hedrick said Do and his wife had rented the rink for two hours from 5:30 p.m. to 7:30 p.m. Approximately 35 people were there at the time of the shooting.
Michelle Ta, was a youth leader at the Vietnamese Martyrs Catholic Church in Arlington.
Her co-worker, Simon Nguyen, said the past few days have been torture.
"This morning, I woke up and the first thing that came to mind was that it was all just a nightmare," he said.
"Why did she leave us, you know... We love her very much, and the kids really love her," Nguyen said.