As Kaufman County district attorney, Mike McLelland vowed to get justice for a colleague who was slain outside the courthouse two months ago.
Today, authorities are vowing to do the same for McLelland and his wife, Cynthia, who were found shot to death inside their Forney, Texas home on Saturday.
The FBI, Bureau of Alcohol, Tobacco and Firearms, Department of Public Safety, and the Texas Rangers have joined the investigation, probing possible links between the death of assistant district attorney Mark Hasse two months ago and the shooting deaths of the McLellands. RELATED: Cops Eyeing Possible Accomplices in Prisons Chief Death
Authorities are expected to hold a news conference later this morning to share any available information.
On Saturday, police confirmed the shooting deaths of the McLellands in their home, but declined to release any additional information.
Sources told ABC News affiliate WFAA-TV in Dallas that a police officer friend went to check on the couple Saturday night and found the front door of their home open. When he walked inside, the sources said the officer discovered Cynthia McLelland dead in a front room of the house and Mike McLelland dead in a hallway, as though he had tried to escape the assailant.
The rural town was turned into a crime scene Saturday night and left neighbors shaken.
"We've lived here for years and we've never had anything like this happen before and for it to happen so close to home is very very scary," neighbor Vanessa Hernandez said.
The task force investigating the murder of Kaufman County Assistant District Attorney Mark Hasse was also at McLellands' home.
Hasse was gunned down execution-style outside of the Kaufman County Courthouse on Thursday, Jan. 31, just before 9 a.m. by one or two unknown assailants as he walked from his car to the courthouse in Kaufman, southeast of Dallas.
The assailants, who may have been masked and dressed in black, fled the scene in a silver four-door sedan.
Hasse, 57, had been a longtime felony prosecutor for the Dallas County District Attorney's Office, according to WFAA-TV. He headed the organized crime unit in Dallas in the 1980s. He started work in Kaufman County three years ago.
McLelland had vowed to hunt down Hasse's killer.
"He knows and I know there will be a reckoning," McClelland said at Hasse's memorial service, WFAA reported. "Too many people are focusing on that. That's not going to be a problem."
Authorities have also been trying to determine whether Hasse's killing was related to the murder of Tom Clements, Colorado's prison director, last month.
The Colorado man implicated in Clements' murder, Evan Ebel, was killed in a shootout with police in Texas two days after the killing.
He was pulled over by police in Texas and fired at deputies, launching a high-speed chase and shootout that ended when he was fatally struck by police gunfire.
Ballistics testing showed that the gun found on Ebel in the Texas shooting was the same one that was used to kill Clements. Police are trying to determine whether there are any other suspects who acted with Ebel in the murder.
Ebel is also a suspect in the murder of a pizza delivery man last Sunday, March 17, in Denver.