Before his death, McLelland had wondered if a white supremacist group was behind the killing of Hasse.
"We put some real dents in the Aryan Brotherhood around here in the past year," McLelland told The Associated Press.
McLelland said Hasse wasn't involved in the Aryan Brotherhood of Texas investigation, but his office was one of numerous Texas and federal agencies involved in an investigation that led to the indictment last year of 34 alleged members of the group -- including four of its senior leaders -- on racketeering charges.
And while detectives were investigating that angle and many others, others focused closer to home. The recent trial of a local elected official had made some feel uneasy.
The 2012 trial of Eric Williams, Kaufman County's then-justice of the peace was big news in the area.
"It was a mega-trial for a little community, the sense of it - it was a big trial," said Denise Bell of the Forney Post newspaper.
Williams lost his job as a justice of the peace after surveillance video showed him taking county computer equipment.
He was found guilty of felony theft, got two years probation and lost his law license.
Neighbors say his life was turned upside down.
In a statement filed with the court after his conviction, Williams denied the thefts and called the loss of his law license "a life long sentence."
"I will have to seek another career, with a felony I will not be able to earn what I am used to," he said, adding that it would be his wife, who he said was on disability, and his aging parents who would suffer the most.
After the killings, investigators interviewed Williams, meeting him at a Denny's. They asked him to take a gun residue test which he did. It came back negative.
Williams, through his lawyer, denied any involvement, said he was cooperating. He said he understood why he was being questioned.
Williams, his attorney said, held no grudges.
Last week, officials arrested Williams and accused him of sending threatening emails to investigators after McLelland's death.
At the time, investigators did not say if Williams was being investigated for the string of killings.
That arrest left many, who had been searching for answers for so long, with more questions.
Then Williams' wife was arrested Wednesday and an arrest warrant made public that seemed to provide the answers.
According to the warrant, the wife described her role and said that her husband, Eric Williams, fatally shot Hasse and the McLellands.
"During the interview the defendant gave details of both offenses which had not been made public," the arrest affidavit said.
Focus on the Williams had intensified over the weekend after authorities carried out searches of their home as well as a storage unit.
An FBI spokesman said investigators recovered a cache of guns and a police-style vehicle.
Witnesses reported seeing one like it in the McLellands' neighborhood around the time of their killings.