A TEXAS TOWN IS ON EDGE, WITH SOMEONE KILLING PROSECUTORS - WAS IT A GANG HIT, OR COULD THE KILLER BE ONE OF THEIR OWN?

"48 HOURS" INVESTIGATES IN "TARGET JUSTICE" ON SATURDAY, FEB. 13 AT A SPECIAL TIME - 8:00 PM, ET/10:00 PM, PT

A Texas town was on high alert after a prosecutor was murdered outside the courthouse. Was he the target of a white supremacist group out for revenge? Kaufman County District Attorney Mike McLelland vowed to get the killer. Then McLelland was killed.

Richard Schlesinger and 48 HOURS investigate the attacks on prosecutors and their families, which put a town on edge and left investigators on the hunt for whoever did it, in "Target Justice" to be broadcast Saturday, Feb. 13 (8:00 PM, ET/10:00 PM, PT) on the CBS Television Network.

In a daring daylight attack, Assistant District Attorney Mark Hasse was shot dead just outside the courthouse one day in January 2013.

"It was - you know - a real whodunit at that point in time," says Lt. Eric Kasper of the Texas Rangers.

"I hope that the people who did this are watching," McLelland said at a press conference soon after. "We're going to pull you out of whatever hole you're in, and we're going to bring you back and let the people of Kaufman County prosecute you."

He never got the chance. In March 2013, McLelland and his wife Cynthia were killed in their home.

"I was shocked for two or three seconds," says Krista Ball, McLelland's daughter from his first marriage. "And I just broke down. The first thing you think of when you hear something like that is, you know, did - how long did they suffer?"

Who would want the prosecutors dead? Initially the investigation focused on the Aryan Brotherhood, a white supremacist group in Texas, one of the most violent prison gangs, which declared it would get revenge against law enforcement. For instance, two months after Hasse was killed, a member of a Colorado prison gang shot a sheriff on a Texas highway. But there was someone else on Hasse's list of cases police spoke with as well. Eric Williams, a lawyer and justice of the peace, had been busted for stealing computer monitors from a county office. Hasse, under McLelland's guidance, prosecuted the Williams case.

Police checked Williams out. They found no gunshot residue on his hands, and initially, Williams had a credible alibi.

Meanwhile, McLelland knew he was at risk, too. "When you deal with bad people," he said then, "You know that there's a potential for these bad people to do something bad to you."

But who was it?

The investigation turned when police got an email with a tip - a tip that seemed like a taunt to investigators. Three weeks after the McLellands' deaths, Eric Williams was charged with capital murder.

Turns out, Williams didn't act alone.

Schlesinger and 48 HOURS report the story through interviews with prosecutors, investigators, Hasse and McLelland's coworkers, and in interviews with McLelland's children JR McLelland and Krista Ball. 48 HOURS: "Target Justice" is produced by Tom Seligson, Allen Alter and Susan Mallie. Lucy Scott and Claire St. Amant are the field producers. Michael McHugh is the producer-editor. Marlon Disla, Mike Mongulla, Alan Miller, Marcus Balsam and George Baluzy are the editors. Peter Schweitzer is the senior producer. Susan Zirinsky is the senior executive producer.

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