San Bernardino sheriff’s Detective Jeremiah MacKay had a 4-month-old baby boy at home as he rejoined the search on Bear Mountain for a murderous ex-cop at 5 a.m. Saturday.

MacKay at one point paused in the hunt for former LAPD officer Christopher Dorner and spoke with a reporter from the Associated Press.

“This one, you just never know if the guy’s going to pop out, or where he’s going to pop out,” he said of the maniac who had already killed three. “We're hoping this comes to a close without more casualties. The best thing would be for him to give up.”

MacKay finished another long day of searching and returned home to his wife of two years, Lynette Quinata MacKay, and their baby boy. The 35-year-old detective had been so excited about the boy’s pending arrival that he posted a sonogram on his Facebook page back in March. Another photo shows the boy in his first days, the resemblance to his dad already clear.

MacKay was back out on the mountain Sunday, Monday, and Tuesday.

“Was up there,” he posted on the same Facebook page where his family photos appeared.

“Watch your six,” a friend commented.

To “watch your six” is to keep alert for a threat approaching from behind. MacKay was a department firearms instructor, so he was no doubt mindful of the danger of becoming so fixed on “12 o’clock” directly ahead that you forget “6 o’clock” to the rear.

But all the caution and training in the world could not have kept him from harm when Dorner suddenly did pop out Tuesday afternoon, blazing away with an automatic weapon.

“Shots fired!” a voice announced over the radio. “Officer down!”

“Automatic fire coming inbound!” said another voice.

MacKay and another deputy were wounded when exchanging fire with Dorner, who sought refuge in a cabin, apparently also hit.

“Is it possible to extract the wounded officer?” asked a voice on the radio, not specifying whether it was MacKay or his partner. “The deputy is still down in the kill zone.”

MacKay’s fellow officers braved being shot themselves as they got him and the other wounded cop out of the line of fire and to a helicopter that touched down at a designated landing zone 400 yards away.

MacKay was beyond saving when he arrived at the hospital. His comrade underwent emergency surgery and was expected to live. Two other helicopters touched down back at the scene in the event more officers were hit.

“We have the suspect holed up in a cabin,” a voice on the radio now said. “We have been trading shots with him for the last 20 minutes.”

Rather than risk losing anybody else, the cops employed “burners”—tear-gas canisters—that had an incendiary effect. The standoff ended as the cabin became engulfed in flames, a conclusion that took on a twist if you knew that MacKay was the son of a retired San Bernardino firefighter.

MacKay also had been a bagpiper and the sergeant-at-arms of the Inland Empire Emerald Society. He had been expected to play February 15 at Saint Practice Day, a worldwide simultaneous toast as well as a fundraiser for the Fallen Officer Memorial Fund. His wife had posted on Facebook that she planned to attend.

“We will raise our pints precisely at 8:00 PM for the worldwide simultaneous toast,” the announcement for the event read. “Our bagpiper will be playing traditional Irish tunes. Sport your kilts and get your craic on!”

Instead, MacKay will be the latest of the fallen officers who are remembered, preceded by Riverside police officer Michael Crain, who was killed by Dorner at the start of the rampage and buried Wednesday. Crain left two children, a 10-year-old boy and a 4-year-old girl.

Whoever plays the pipes Friday will be playing for all of them, including the baby boy who now will know his father only by the stories of his music, his smile, and his courage.