HOUSTON -- It's a mystery to investigators why Javier Cortez was bound and beaten to death by home invaders in southeast Houston, KPRC Local 2 reported Tuesday.

As police look for clues and several suspects, 37-year-old Cortez's wife, Gabriella, searches for the words to tell her two daughters that their father is gone.

"I just worry about my daughters," she said. "I don't know what to tell them. They're 5 and 9."

Investigators said the home invasion happened at about 2 a.m. Tuesday.

Police said two to four males forced their way into the house in the 8100 block of Lenore in southeast Houston. They found Cortez and his mother inside.

"They duct taped the victims and assaulted them during the home invasion," HPD detective C. Abbey said. "They conducted a search within the house. What they were looking for, we're not exactly sure."

Cortez was severely beaten. Police said that he suffered blunt trauma to the head, but his exact cause of death is unknown.

Investigators said they believe the incident was not drug related, but they were not sure about the motive behind the crime.

"Most of the time, home invasions are not random crimes," Abbey said. "Generally, the suspects know who the victims are going to be. As far as relationship between the suspect(s) and victims in this crime, we don't have that yet."

But Cortez's wife said she has an idea. The two have been separated for five months, but she said her husband was a contract worker.

She told Local 2 that he was recently threatened after getting into a disagreement with some of his laborers.

"Something about the equipment, they were fighting about," Cortez's estranged wife said. "They didn't want to get it down and this and that, and he said, 'Well, I know where your family lives.'"

After that threat, Gabriella said Cortez warned her to be careful, but police said it was the victim's mother who wound up in danger. They said she witnessed her son's brutal murder.

"(She's) obviously very traumatized by what happened here," Abbey said. "She was only here a day or two. Not here in this house very long at all."

Police did not release descriptions of the attackers and were not able to get a description on their vehicle.

Anyone with information that could help the investigation is asked to call the Houston Police Homicide Division or Crime Stoppers at 713-222-TIPS.