Jason "J.T." Ready, a well-known anti-illegal immigrant extremist and white supremacist who was running for Pinal County sheriff in Arizona, is dead in an apparent murder-suicide after a shooting rampage which left four others dead, including a toddler, authorities said Wednesday.

Investigators believe Ready, the founder of the U.S. Border Guard, a fringe militia group dedicated to hunting undocumented immigrants and drug gangs in the Arizona desert, killed four victims, ranging from a 2-year-old toddler to a 47-year-old grandmother, before killing himself. 

Early indications from the investigation point to a domestic violence dispute that may have triggered the shooting rampage in Gilbert, a quite Arizona suburb southeast of Phoenix, according to police.

Before his involvement with White supremacy became public, Ready was a prominent figure in Arizona's movement to crack down on illegal immigration. He was a member and spokesman for the Minutemen Project in 2005, a national anti-illegal immigration militia. He was a Maricopa County GOP Precinct Committee member, ran for Mesa City Council in 2006, and rubbed shoulders with Russell Pearce, author of SB 1070 and eventual president of the Arizona State Senate. 

But, as Ready's participation in the National Socialist Movement became public in 2007, he was marginalized and his activities disavowed.

Ambulances and dozens of police officers were dispatched to the site of the crime. That was 90 minutes after local police received a call about a domestic violence incident involving Ready and his girlfriend, myFOXphoenix.com was told by authorities at the scene.

Found dead alongside Ready were his girlfriend Lisa Mederos, 47, her daughter Amber Mederos, 22, Amber's boyfriend, Jim Hoitt, 24, an army veteran who served in Afghanistan, and Amber's daughter, Lilly, 16 months old, who was rushed to the hospital where she died. 

Balafas said the three females were discovered inside the house; the two men were found outside. The witness mentioned by Balafas is another of Lisa Mederos' daughters, Brittany Mederos, 19, was at the house and heard gunfire, but was not wounded.

Reports said she either survived the spree or was the person who discovered the bloodbath.

"If I had any inkling that this guy was violent or anything like that, there's no way they would've stayed there, my daughters wouldn't have put one foot in that house ... I regret not even looking into it," Hugo Mederos, Lisa Mederos' Florida-based ex-husband, said.

Friends of the victims talked about them with the Arizona Republic newspaper. Friends and neighbors described Mederos and her boyfriend Hoitt as a "young couple, just starting out." Neighbors expressed outrage and shock. 

"You want to commit suicide? How dare you take children's lives," Cathi Rand told the Republic. 

Meanwhile, the U.S. Border Guard's webpage, which features several pictures of J.T. Ready armed with an automatic weapon, lamented its leader's death.  

“The U.S. Border Guard is extremely saddened by the untimely loss of our founder, J.T. Ready, and the other souls lost in such a senseless act of violence,” the group said in a message posted to its Facebook page. “God bless you, J.T. You will be fiercely missed.”  

Until recently Ready, 39,  had his sights set on the Pinal County Sheriff's office after Sheriff Paul Babeu announced plans to run for Congress.

A Facebook page promoting J.T. Ready’s campaign for Pinal County Sheriff implied that drug traffickers were responsible for the killings.

“Reports are unconfirmed that a cartel assassination squad murdered JT Ready and several of his friends and family this afternoon in Gilbert Arizona,” said a comment posted Wednesday.

Ready has been characterized by the Southern Poverty Law Center as an "outright Neo-Nazi" advocating deadly force on the border and quoting him as once saying,  "I firmly believe in having a minefield across the border." 

In 2010, Ready formed "The American Border Guard," which he referred to as "the Minutemen on steroids." The organization came after Arizona passed SB1070, the nation's toughest immigration enforcement bill.

When Ready ran for Mesa City Council in 2006, he made headlines that March when he fired a pistol at a Latino man armed with a BB gun, according to the Southern Poverty Law Center. His campaign came to an end, after it came to light that Ready had been discharged from Marine Corps after a court martial.

Early on, as an aspiring Republican politician, Ready was acquainted with many of the political leaders steeped in Arizona’s anti-illegal immigration movement.

Russell Pearce, the author of Arizona’s tough immigration law, SB 1070, helped ordain Ready as an Elder in the Mormon Church in 2004, according to the Phoenix New Times, and endorsed Ready’s failed 2006 run for Mesa City Council.

Pearce disavowed his relationship with Ready, however, shortly after Ready began to publicly appear and speak at Neo-Nazi rallies and activities in 2007.

“When we first met JT he was fresh out of the Marine Corp and seemed like a decent person,” Pearce said in a press statement Wednesday. “When I learned the truth about him, I made it clear how wrong I thought it was and I worked to remove him from our Party.”

By the time Ready launched his bid for Pinal County Sheriff in January, however, the lifetime Republican had switched to the Democratic Party, according to election records cited by news web-site Talking Points Memo.

Ready told Talking Points Memo he respected the Democratic Party’s Jim Crow history, noting his admiration of Alabama segregationist Gov. George Wallace.

Ready also applauded President Barack Obama for sending more National Guard troops to the border and for deporting more immigrants than any president in history.

The Obama administration removed nearly 400,000 immigrants in the 2011 fiscal year.

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