Jeremiah MacKay was a regular at Liam’s Irish Pub in Colton.

He always had a pint of Guinness and a smile, said Yara Alves, the bar’s owner. He had Irish roots, and he’d show up, guaranteed, every St. Patrick’s Day wearing a kilt and bringing his bagpipe.

“He never had anything sad or negative to say,” Alves said. “It was as if he never had a bad day.”

Alves choked up as she spoke about MacKay, 35, a San Bernardino County sheriff’s deputy who was killed in a firefight Tuesday in an isolated area near Big Bear. Police said the gunman was Christopher Dorner, a former Los Angeles Police Department officer bent on revenge over his dismissal from the agency in 2009.

WHO THEY WERE: Victims in the Dorner case

A second deputy, Alex Collins, was wounded in the gunfight, San Bernardino County Sheriff John McMahon said. Collins has undergone multiple surgeries and is expected to make a full recovery.

McMahon said the deputies who responded to the cabin where Dorner barricaded himself are “absolutely true heroes.”

“The rounds kept coming” from the cabin, he said, “but the deputies didn’t give up.”

Dorner also is believed to have killed three other people, including Riverside Police Officer Michael Crain, who was shot in his marked patrol vehicle. Crain was buried Wednesday. On Feb. 3, Monica Quan, daughter of a retired LAPD captain, and her fiance, Keith Lawrence, were found shot to death in an Irvine parking garage in what police believe were the first of Dorner’s crimes.

On Thursday, authorities confirmed that the charred remains found in the burned-out cabin were Dorner’s.

For days, MacKay, a 14-year veteran of the department, was involved in the massive manhunt for Dorner in the mountains around Big Bear.

“We knew he was up there,” MacKay’s cousin Jennifer Goehring said. “We were praying for his safety, but never in a million years would we have thought this would happen.”

MacKay posted photos from the mountains on his Facebook page, joking about how he — who grew up in the San Bernardino Mountains — was one of the only officers wearing short-sleeved shirts in the snow.

On Saturday he told an Associated Press reporter that he knew the danger as he scoured the mountains for Dorner: “This one, you just never know if the guy’s going to pop out or where he’s going to pop out. We’re hoping this comes to a close without any more casualties.”

On Sunday he was pictured on the front page of The Times, his eyes squinted as he put on a hat. He posted a photo of the newspaper on Facebook, making fun of his facial expression, Alves said.

San Bernardino County Sheriff’s Capt. Lee Hamblin said he was responding to the call of a gun battle when he heard “Officer down.” He said his worst fear was soon confirmed when he learned MacKay had been killed.

“Although we’re glad it’s over,” Hamblin said of the manhunt, “the price we paid was way too high.”

MacKay joined the department in July 1998, Hamblin said. He worked in the jails, as a detective at the department’s Big Bear station and most recently as a deputy in the department’s Yucaipa station.

He was married to Lynette Quinata MacKay and had a 7-year-old stepdaughter and a 4-month-old son, Goehring said. He was thrilled to be a new father. His family, she said, made him the happiest man in the world.

On Thursday, a steady stream of people stopped by a makeshift memorial outside the Yucaipa station.

Janet Lopez, 55, placed flowers and a note at the memorial. MacKay, she said, had taken a liking to her father, who suffered from renal failure. MacKay would “go over and cheer him up, get him to walk,” she said.

Family, friends and co-workers described the deputy as having a big personality, a big heart and a big, loud laugh. It was difficult to be sad around him, they said.

It was MacKay’s laugh that first caught Edward Knuff’s attention years ago in Liam’s Irish Pub.

“He was a little boisterous, always fun,” Knuff said.

Knuff, a commercial photographer, said he met MacKay at the pub for a meeting of the Inland Empire Emerald Society, a nonprofit that raises money for the families of fallen law enforcement officers.

Now the organization is raising money for MacKay’s family.

hailey.branson@latimes.com

adolfo.flores@latimes.com

Times staff writer Joseph Serna contributed to this report.