Authorities said his plan was thorough and detailed. Pardo had a getaway car, an airplane ticket to the Midwest, several guns, and high-powered ammunition only sold outside the state.
He launched the attack on Christmas Eve, putting on his Santa Claus suit, arming himself with four guns and barging into a party at his ex-relatives' home. He then killed nine people and torched the home.
Police Lt. Pat Buchanan said Pardo knew his mother had been invited to the party and intended to kill her because he felt she sided with his ex-wife in their divorce. Lucky for her, Buchanan said, she felt ill and opted to stay home.
His ex-wife's attorney also was apparently a target. Police Chief Kim Raney said Pardo left a rented vehicle near the attorney's Glendale home the day of the shooting and filled it with maps, clothes and a fuel tank.
But Pardo never made it to the vehicle. He was burned while torching the in-law's house and later killed himself at his brother's home.
If Pardo had lived, "his next destination was Glendale," Raney told hundreds of mourners who gathered at a local school Monday to offer each other comfort.
The residents, many wearing orange ribbons to remember the victims, gasped as Raney explained the latest details of the investigation. Raney pledged he would "try to bring sense to what was a senseless act."
The quiet community of backyard pools and wide boulevards was still coping with the bizarre and violent crime. Elderly women took notes on city officials' remarks from the meeting and women wiped tears from their eyes during a prayer.
Mayor Kevin Stapleton asked residents to respect the privacy of the surviving family members and their neighbors.
"I know people want to go by and see the location. But keep in mind that people live there and we need to get them some return to normalcy," Stapleton said.
County mental health counselors and trauma specialists distributed pamphlets and referrals, while neighbors hugged and shook their heads in grief and confusion.
David Singer, a psychiatrist and volunteer trauma therapist, advised parents on how to talk to children who might be confused and frightened by the idea of Santa Claus committing such a horrible crime.
"He was so full of hate that he had to disguise his hate by dressing up as someone full of love -- Santa Claus," Singer said.
Pardo had planned to eventually flee to Canada following the killing spree but suffered third-degree burns in the fire -- which melted part of the Santa suit to him -- and decided to kill himself instead, investigators said. His body, with a bullet wound to the head, was found at his brother's home about 40 miles away.
The rented compact car he had driven to his former in-laws' house was rigged to set off 500 rounds of ammunition and later exploded outside his brother's home. No one was injured.
Police found a second car rented by Pardo late Saturday, but Buchanan said the bomb squad did not find any explosives in that vehicle.
Not far from the school, the charred remnants of the destroyed home still smelled of smoke. A pile of votive candles, flower and stuffed animals lay outside a chain-link fence protecting the site.
Jill Amparan placed a bouquet of flowers on the curb and said a prayer with her friend, Elizabeth Chavez. Still dressed in their scrubs after leaving their jobs at a medical clinic, the women expressed anger at Pardo's actions.
"People die every day but the way this happened is awful," Amparan said.
Chavez said her 9-year-old daughter has been riveted by the story of a man dressed as Santa Claus committing such a horrible crime.
"She brought a newspaper article to day care to show her teacher," she said.
The whole incident left both women wondering what made Pardo so desperate to get back at his ex-wife by hurting the ones she loved.
"He had a house, friends, family and a church community. That's supposed to help you when things get bad," Amparan said.