DALLAS (CBSDFW.COM/AP) – Dallas police have issued a capital murder warrant for a 16-year-old girl suspected in the fatal shooting of a grandfather who was protecting family under attack from masked invaders at his home.

Police say 66-year-old Lorenzo Moreno died in the attack early Sunday.

“There’s no way to put closure on something like this,” said Christina Lopez, Moreno’s niece. “Your whole life changes.”

Police say at least six suspects stormed into Lozenzo’s house to confront his 15-year-old granddaughter and an argument ensued just after midnight on Sunday. The dispute turned violent and the attackers beat Moreno’s granddaughter, his 62-year-old wife and their 34-year-old son. The three were later treated at a hospital and released.

Police have not identified the teenage suspect nor anyone else involved in the attack, and did not release details of the argument.

Lopez said Moreno’s wife watched the entire incident unfold.

“When she heard the gun shot she just screamed and cried,” he said. “She just couldn’t believe it.”

Moreno’s 62-year-old wife was beaten during the attack, but she managed to pull off one of the suspect’s masks. Under it, police say, was the 16-year-old suspect.

A television was removed from the house during the attack.

“They took a life. They took a good husband, my aunt’s husband,” said Lopez. “They took a good father and grandfather. They took the life of a human being. They need to give up themselves and turn themselves in.”

(The Associated Press contributed to this report)