'He fought them,' father says of son killed on his birthday defending his family in Texas home invasion

Security video of a car speeding from the Texas home of a father gunned down on his 29th birthday while defending his wife and two young children from intruders was released by authorities desperate to identify the suspects and bring them to justice.

Brenton Estorffe, an Australian native raising his family in the Houston suburb of Katy, was shot to death early Wednesday while attempting to fight off at least two men who broke into his residence, according to Fort Bend County Sheriff's Office investigators.

"He wrestled those two blokes away from his wife and kids," Estorffe father, Michael Estorffe, told The Australian newspaper before flying from Australia to Texas to be with his son's grieving widow and children. "That’s when they shot him. Unfortunately, he paid the highest price."

The killers remained on the run on Sunday. A $25,000 reward was offered by the Fort Bend County Crime Stoppers for information leading to the arrests and prosecution of the killers.

Estorffe's death sent shockwaves from the Lone Star State to Australia, where the headline in Estorffe's hometown newspaper, The Courier-Mail, screamed, "Australian man, Brenton Estorffe, shot dead in Texas home while confronting intruders."

Fort Bend County Sheriff Troy Nehls requested the public's help in finding the owner of a light-colored, four-door sedan with a sunroof that was spotted on home security video arriving and speeding away from Estorffe's block around the time of the shooting. He said the tail lights on what he described as a "vehicle of interest" may not have been operating properly.

Nehls said at least a dozen investigators are working around the clock to solve the homicide of a "loving husband and a loving father."

"He gave his life in defense of his family. What more honor can you bestow upon an individual than that," Nehls, a retired Army Reserve major and recipient of two Bronze Star medals, said of Estorffe.

"They're going to pay for this," Nehls said of the killers during a news conference on Friday, attended by Estorffe's widow, Angeleanna.

Staring into a bank of news cameras, he told the killers to surrender, saying, "You came into the wrong county."

Nehls said there could be more than two suspects involved in the homicide.

"There could have been another individual inside that vehicle of interest that might have been the getaway driver. We don't know," Nehls said.

Det. Thomas Cantu, the lead investigator on the case, described the two intruders Estorffe confronted in his home. He said one was about 5-foot-11, had a medium build, a dark complexion and was wearing a dark-colored hoodie with the hood covering his head. He said the other intruder was about 6 feet tall, had a slender build, a dark complexion and a buzz-cut hairstyle.

The slaying unfolded just after midnight on Wednesday when Estorffe and his wife were startled awake by glass breaking at the rear of their home, Nehls said. Estorffe's children, 1-year-old Eliana and 3-year-old Asher, were asleep in the house.

"Try to put yourself through this: somebody breaks the glass. You hear glass breaking at the back of your home. Two individuals enter the home. They startle you. You wake up and then all of a sudden a confrontation takes place and then the next thing you hear are gunshots," Nehls said.

"Brenton gets up, confronts two individuals inside the residence, at which point in time he was shot and killed," Nehls said. "Brenton was there to protect his family."

He said Estorffe's wife and neighbors called 911. Estorffe was pronounced dead at the scene.

"Help me please … ohh … someone just broke into my house and shot my husband," Angeleanna Estorffe said in the 911 call released by authorities. "I just heard glass shattering and then my husband jumped up and took off after them … and they just … they started shooting."

"A few minutes later we have a vehicle of interest ... leaving the neighborhood. We see the same vehicle entering the neighborhood before the 911 calls took place," Nehls said, asking anyone who has seen the vehicle to contact investigators immediately.

Nehls and Cantu said it remains under investigation whether Estorffe and his family were targeted or if the culprits went to their home seeking the previous owners.

Cantu said Estorffe and his family moved into the home about six months ago.

Nehls said the intruders must have known the home was occupied and that children were inside the home because cars were parked in the driveway and the house was decorated for Halloween.

"Anybody would know that there were obviously children in that house. I mean there's Halloween decorations. You almost got to make the safe assumption, these individuals knew somebody would be at home. But yet they still had the audacity to break a window and enter the home. That's a little unusual," Nehls said.

He said the neighborhood is generally "very quiet, very safe," and added that of the seven homicides this year in the county, of which there are more than 500,000 residents, six of the cases have been solved.

Estorffe was originally from Mooloolaba on the Queensland's Sunshine Coast of Australia, his family said. He moved to the United States in 2011 to attend college at Southern Virginia University, where he played football. At one point, according to his family, Estorffe had aspirations of someday playing in the NFL.

Estorffe got married in 2015 and he and his wife decided to settle down in Katy, Texas, and Estorffe took a job at a car rental company, his family said.

A crowdfunding page established for Estorffe's family had raised more than $35,000 as of Sunday afternoon.

"We will stop at nothing," Nehls said. "We will investigate, we will investigate, we will investigate until we can bring these individuals to justice."

ABC News' Emily Shapiro contributed to this report.