It's been four days since Fort Worth police arrested a teacher in the shooting that left two roommates dead after all three men attended a Halloween party early Sunday, but the victims' friends and families are still asking questions about the suspect's motive.

"The murderer did not know our sons. The shooting was completely senseless," Paige Hudson Garcia, mother of victim Phillip Evans, wrote in a Facebook post about her son and Daniel Haros, the second victim in the shooting.

Cary Heath, a 35-year-old Cedar Hill ISD middle school teacher and Air Force veteran, was arrested Monday on capital murder charges. He remains in the Tarrant County Jail in lieu of $1 million bond.

Cary Heath, 35

Sgt. Marc Povero, a Fort Worth police spokesman, said Thursday that Heath is not cooperating with police, and detectives have yet to determine a motive.

Haros and Evans, both 25, walked to the Halloween party about 3 a.m. in the 900 block of Buffalo Springs Drive just to say hello, said members of Haros' family.

According to police, they had a "friendly and cordial" conversation for less than five minutes with the couple hosting the party and Heath and his wife, Tiffany.

Police say the party disbanded, but minutes later Heath came out of his house with an assault rifle and allegedly shot Haros and Evans down the street from the party in the 800 block of Buffalo Springs Drive.

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"Our sons were defenseless and unarmed (in their 'pajamas' in the front yard of their home) - truly innocent victims by all accounts, in every sense of the word," Garcia wrote in a Facebook post.

Police say Heath went back to his home, admitted to his wife that he killed Haros and Evans and told her to clean the blood in the safe where he keeps his firearms.

"This is the last time I will see the baby. I killed two people," said Heath, who has four children, according to the affidavit.

Jesse Haros, Haros' uncle, said Tuesday that the family couldn't imagine why anyone would attack Haros or Evans, who had been best friends since childhood and played soccer for Burleson High School together.

"They were good, hardworking, happy, responsible men," Haros said. "They were very respectful.

"There was no motive," he added.

Friends of Haros and Evans echoed the families' confusion about the shooting.

"There's no explanation for it," Kevin Morgan, a friend of the victims, told KXAS-TV (NBC 5). "I believe they did nothing. They did nothing. Did the guy just flip out? That's what the question is. That's what we want to know."

A memorial celebration for Haros and Evans will be held at 9 p.m. Thursday at Dalton's Corner, a bar the victims frequented in Burleson. Ten percent of all sales will be donated to the victims' families.

Attendees will honor Haros and Evans with a "Bud Light Chug," like the victims used to do to start off a night, according to WFAA-TV.