Gilbert police spokesman Sgt. Bill Balafas said Thursday that police believe Jason Todd Ready, 39, was the gunman in Wednesday's shootings in a home in Gilbert.

Ready lived in the home with a woman who was among the dead. Media reports say that the four others killed include Ready's girlfriend, and the woman's daughter and granddaughter.

Ready was known in Arizona for organizing a militia in the desert with the goal of finding illegal immigrants and drug smugglers. Known as "J.T.," Ready led an outfit known as the U.S. Border guard that dressed in military fatigues and body armor and carried assault rifles during patrols for illegal immigrants in the desert south of Phoenix.

Police identified the others killed as 15-month-old Lily Lynn Mederos; 23-year-old Amber Nieve Mederos; 47-year-old Lisa Lynn Mederos and 24-year-old Jim Franklin Hiott.

Balafas has said that all the evidence points to the shooting being related to domestic violence. But he said investigators aren't sure what triggered the shooting.

Officers have recovered two handguns and a shotgun.

The shootings occurred in a subdivision filled with stucco homes with red-tile roofs.

Members of the federal Joint Terrorism Task Force and FBI agents removed what Balafas said were military-grade ordnance, munitions and two barrels of chemicals found behind the home.

Ready and Hiott were found dead outside the home, and the bodies of two women were inside. The toddler was found inside the home showing signs of life, but later died at a hospital.

A teenager in the house heard arguing followed by gunshots, Balafas said. She came out of a back room and found the bodies.

About three hours after the shooting, a man walked up to the police tape, pointed to the crime scene and said, "I have a daughter who lives in that house."

Police pulled him behind the tape and out of view. Several seconds later, a loud, anguished cry could be heard. Minutes after, the same man was weeping and left the scene with police.

Ready took offense at the term "neo-Nazi," but acknowledged he had identified with the National Socialist Movement, an organization that believes only non-Jewish, white heterosexuals should be American citizens and that everyone who isn't white should leave the country "peacefully or by force."

"We're not going to sit around and wait for the government anymore," Ready said in a July 2010 interview with The Associated Press. "This is what our Founding Fathers did."

Violence touched his life in ways beyond his militia work. Ready knew and organized border patrols with Jeffrey Hall, a California white supremacist shot and killed last year by his 10-year-old son.

Balafas said officers have been called to the home previously for domestic disputes, Balafas said. He had no details of those calls or if they involved Ready.

Gary Davis, who also lives in the neighborhood, said: "There's no excuse for taking a child's life."

"Nothing ever happens in this neighborhood," Davis said. "It's a shock to us."