ARLINGTON, Texas (AP) -- Darrell Roberson came home from a card game late one night to find his wife rolling around with another man in a pickup truck in the driveway.

Caught in the act with her lover, Tracy Denise Roberson -- thinking quickly, if not clearly -- cried rape, authorities say. Her husband pulled a gun and killed the other man with a shot to the head.

On Thursday, a grand jury handed up a manslaughter indictment -- against the wife, not the husband.

The grand jury declined to charge the husband with murder, the charge on which he was arrested by police.

"If I found somebody with my wife or with my kids in my house, there's no telling what I might do," said Juan Muniz, 33, who was having lunch Friday with one of his two small children at a restaurant in the middle-class suburban Dallas neighborhood where the Robersons lived. "I probably would have done the same thing."

Tracy Roberson, 35, could get two to 20 years in prison in the slaying of Devin LaSalle, a 32-year-old UPS employee.

Assistant District Attorney Sean Colston declined to comment on specifics of the case or the grand jury proceedings but said Texas law allows a defendant to claim justification if he has "a reasonable belief that his actions are necessary, even though what they believe at the time turns out not to be true."

Mark Osler, a Baylor University law school professor and a former federal prosecutor, said the grand jurors evidently put themselves in the husband's place: "I can see one of them saying, 'I would have shot the guy, too. I was just protecting my wife.' "

The December night before the shooting, Tracy Roberson sent LaSalle a text message that read in part, "Hi friend, come see me please! I need to feel your warm embrace!" according to court papers. LaSalle apparently agreed.

Darrell Roberson, a 38-year-old employee of a real estate firm, discovered the two, his wife clad in a robe and underwear.

When Tracy Roberson cried that she was being raped, LaSalle tried to drive away and her husband drew the gun he happened to be carrying and fired several shots at the truck, authorities said.

Darrell Roberson's attorney did not immediately return a call for comment.

His wife also was charged with making a false report to a police officer -- for allegedly saying she was raped -- and could get up to six months behind bars on that offense. It was not immediately clear whether she had a lawyer.

She had not been arrested as of Friday afternoon.

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