Montrose, Calif. ? Before donning the Santa Claus suit that would deceive his first victim, Bruce Pardo spent months plotting his Christmas Eve massacre behind a mask of friendliness that fooled his neighbors, lawyer and the ex-wife he killed along with eight of her kin.

As early as last summer, Bruce Pardo was purchasing ammunition and guns and ordering supplies to build a device to torch his former in-laws’ home. In early fall, the unemployed electrical engineer ordered a custom-made, extra-large Santa Claus suit from a seamstress.

By December — as his divorce became final — Pardo put the final touches on his horrific plan by renting two getaway cars and booking a flight to Illinois.

Yet by all accounts, the 45-year-old man moved through life during those crucial six months as if nothing were amiss. His divorce attorney said he was always upbeat and even his wife’s attorney said he was civil throughout the nine-month proceedings.

“He was planning that for months,” said Henry Baeza, owner of Montrose Home Bakery where Pardo dined the day of the killings. “And the other 45 years he was a totally normal man. It doesn’t make no sense.”

Plans began in summer

In July, Pardo began purchasing guns and hundreds of rounds of heavy ammunition, and started building a device to spray highly flammable racing fuel in his in-laws’ home, police said.

At about that time, Pardo had lost his six-figure income at ITT Electronic Systems Radar Systems in Van Nuys and was desperately seeking work. His estranged wife, who had moved in with her sister and brother-in-law and was seeking a divorce, was awarded spousal support as his debts stacked up.

By fall, according to court papers, Pardo appeared to be increasingly desperate.

In September, he custom-ordered an extra-large Santa Claus suit from costume maker Jeri Deiotte, whose shop is less than two miles from Pardo’s home in this quiet Los Angeles suburb.

He told Deiotte the $300 suit — complete with boots, belt, glasses and a hat — was for a Nov. 8 holiday party. He said he needed it extra-large so he could be extra-jolly, a request that chills Deiotte in retrospect.

“He wanted it huge, bigger than he was,” said Deiotte, who later called police. “That’s what triggered it to me because I heard on the news that he carried some guns inside.”

Leading up to attack

On Dec. 18, Pardo and ex-wife Sylvia Pardo reached a final divorce settlement: He kept the house and cars, but she got the diamond wedding ring, $10,000, most of the furniture and the couple’s dog, Saki.

Pardo was supposed to deliver a $10,000 cashier’s check to her attorney by Dec. 19, but he never showed up. He told his attorney he was still trying to come up with the cash.

Five days later, cafe owner Baeza chatted with Pardo as he stopped in for his usual raspberry cheese Danish and coffee. This time, he also ordered a turkey sandwich for lunch and ate it in a corner booth, looking out the window at the street bustling with Christmas shoppers.

Baeza still replays that last conversation in his mind, searching for a clue to what happened just 11 hours later.

“He shook hands with me and said ‘Goodbye and merry Christmas to you and your family,'” said Baeza. “And I said ‘You, too’ and he just smiled a little.”

The rampage

Around 11:30 p.m., Pardo approached his former in-laws’ house in Covina 20 miles away and knocked on the door. He had four guns and his fuel-spraying device, disguised as a present.

A little girl excited to see Santa opened the door and he shot her in the face. He entered the house firing, at first indiscriminately and then targeting his ex-wife’s family. At one point, he may have knelt down to shoot a group of family members who dove under a table where they had been playing cards, according to police accounts and 911 calls.

When it was over, Pardo’s ex-wife, her parents, her two brothers and their wives and her sister and her sister’s 17-year-old son were dead — nine of the 25 guests at the annual holiday bash.

Police later said Pardo also intended to kill his own mother, who was to attend the party, but she decided not to go at the last minute because she felt sick. Pardo apparently felt she was siding with his ex-wife in the divorce; the two women remained close friends.

Change of plans

Police believe Pardo cut short his rampage when the fuel from his device ignited before he expected — probably set off by a pilot light or candle. He suffered third-degree burns so severe they seared the Santa costume to his flesh.

“He was probably in a great deal of pain,” said Lt. Tim Doonan, who’s supervising the investigation.

Still, Pardo managed to change out of the suit and knock out lights in the street before he drove to his brother’s house 40 miles away and parked his rented car.

He left the remains of the singed suit in the car, booby-trapped with a trip wire set to ignite black powder and detonate several hundred rounds of ammunition when disturbed.

Then, Pardo broke into his brother’s house and shot himself once in the head.