Last week, the longtime neo-Nazi reportedly walked into a house in a suburb east of Phoenix and killed his girlfriend, a toddler and two other people before killing himself.
In the aftermath, the special agent in charge of the FBI's Phoenix office said agents had been targeting Ready with a domestic terrorism investigation at the time of his death. According to Phoenix television station KPNX, the probe was looking into whether he was involved in desert shootings of immigrants.
If that's true, the April 8 incident was probably not among them.
Deputy Renee Carlson, spokeswoman for the Pima County Sheriff's Department in Tucson, said on Monday that investigators with her agency looked at whether Ready may have been involved in the incident. Ultimately, she said, they cleared him.
"At this point, they are saying that there isn't anything that appears to connect the two," Carlson said, relaying what she was told by investigators. "They've looked into it and there's just nothing at this point."
A spokesman with the FBI's Phoenix office did not return a call for comment.
Carlson said investigators are still trying to figure out who opened fire on the immigrant group. In the past, the sheriff's office said the group was traveling in a pickup truck in a dry riverbed that's often used as a smuggling route when they were ambushed. The only description of the attackers made public so far is that they were wearing camouflage and carrying rifles.
Ready was the leader of a group he called the U.S. Border Guard, a militia-style organization that dressed in camouflage and took armed trips into the desert north of Tucson. Often, when they would come across immigrants trekking through the desert, Ready used to say, he and his fellow group members would hold the immigrants at gunpoint and call for law enforcement to pick them up.
Ready called himself a humanitarian. However, he was not shy about his willingness to use force on illegal immigrants.
In 2010, he advocated for putting landmines along the U.S.-Mexico border as a way to stop the flow of immigration. In an interview that same year, he said he would not hesitate to use violence if confronted in a "deadly force" situation. "We'll kill them," he said at the time. "We will kill the narco terrorists."