Image Credit: ABC News

ABC News' John Santucci reports:

It's been just over a week since J.R. McLelland learned that his father, Kaufman County District Attorney Mike McLelland, and his wife, Cynthia McLelland, were gunned down in their Forney, Texas, home.

"He wanted to be involved in the court system," the oldest son of the first term district attorney told ABC News. "He wanted to be in the courthouse, in the justice system, the whole lay of it. He just didn't want to go up there and be a lawyer. He wanted to be the DA."

Investigators on the federal, state and local level have been trying to figure out who killed the couple in their home on March 30. The bodies of the district attorney and his wife were found, officials said, after a neighbor went by to check on the couple when relatives could not reach them.

J.R. McLelland said his father, 63, and Cynthia McLelland, 65, the DA's second wife, were inseparable.

"The one small thing we can take from this is that they went together," said McLelland, "because that's how they lived."

There have been no arrests in their deaths, or in the death of the county's assistant district attorney Mark Hasse, who was shot outside the Kaufman County courthouse in late January. Investigators still have no leads in the Hasse death and continue to explore ways the two cases may be connected.

"[My father] did express that he missed [Mark Hasse], and he did want to find those who did it," his son said, "just like everyone wants to find who did it; just like in this case we want to find out who did this."

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Surveillance video surfaced from the day before the McLellands were killed, showing the northeast Texas DA shopping at a local gun store. Steven O'Neill Kidwell, owner of Helz Firearms in Forney, told ABC News that McLelland liked to just window shop and stopped in periodically.

"He came in to check up and say hi, and see how sales are. And gun control was such a big issue. His safety was not a concern of his, but his co-workers safety was," said Kidwell.

"He didn't go to a gun store just because [Mark Hasse] got murdered. He went to every gun show in the Dallas/Fort Worth area," J.R. McLelland said.

The McLelland family has extended its thanks to law enforcement, which has worked nonstop to find those responsible for the killings, as well as those in the community and outside the Lone Star State who have sent their well-wishes.

The family remains confident that someone will be held accountable, even if it's "a week from now or a year from now."

"If there's anybody out there, there's $200,000 worth a reward, and I believe it's growing," said McLelland. "Kaufman County is coming together and adding more money to it. If there is anybody out there who knows anything about it we ask that you call. A tip can lead you anywhere."

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The family has asked for privacy and adds that although some have tried to speak on the family's behalf, family members will be the only ones commenting as news develops. In response to statements made by Chris Heisler, who had identified himself as a family spokesman, the Kaufman County Sheriff's Office issued a statement saying in part that Heisler's "self-description as family spokesperson and his statement of the family's feelings are both inaccurate and unauthorized."