Nero, the Yarmouth police dog who was wounded when his handler officer Sean Gannon was fatally shot last week, has emerged as a symbol of hope and healing for his traumatized department.

Yarmouth police Chief Frank Frederickson stopped by Sunday to see Nero and emerged a changed man, as he tells it.

“He was sitting on a pillow with these sad eyes being treated like a king. I walked out to the waiting room and I was like, ‘My God, I feel really good right now,’ ” Frederickson said yesterday. “It was the best I’d felt since this happened. And what I saw is Nero is feeling this, too — this vibe that’s helping him along, because he shouldn’t be alive.

“What Nero is bringing to us is something to root for, something to be hopeful for out of this tragedy. We’ll never replace Sean, but that hope that Nero will be our hero and live on will help a lot of us heal,” Frederickson said.

Hundreds of K-9 officers and their dogs are expected to stand sentry in homage to Gannon and Nero at Gannon’s wake this afternoon and funeral Mass tomorrow morning at St. Pius X Church in South Yarmouth.

As Nero heals in the intensive-care unit of Cape Cod Veterinary Specialists in Buzzards Bay, the 2 1⁄2-year-old Belgian Malinois’ visitors have included Gannon’s widow, Dara.

Nero’s trainer, retired Yarmouth K-9 handler Peter McClelland, has kept a round-the-clock vigil over the injured patrol dog, who was shot though the snout when Gannon was shot in the head while serving a warrant last week. Thomas Latanowich, 29, has been charged with murder.

McClelland raised Nero as a puppy, then handed him over to Gannon, to bond with and train.

“Everyone knew I had a relationship with him. I rub his ear and rub his belly and we just hang out,” McClelland, 72, told the Herald yesterday. “I never thought about it happening this way, but I can’t leave him.”

He said has not mentioned Gannon as he tries to comfort the dog, and said he believes Nero is too traumatized and out of his element right now to wonder where his buddy has gone.

McClelland said Nero is slowly being weaned off his medications. “The staff here is over-the-top great,” he said. “I’m getting him outside to go to the bathroom. He didn’t eat until (Sunday), but all the things are coming back.

“He’s not out of the woods, but he’s starting to be a dog again.”

McClelland, who retired in 2010, said it’s “way, way too early” in Nero’s recovery to speculate about whether his law-enforcement career is behind him.

“It’s up to the healing process and up to the dog,” he said.

McClelland said a single bullet pierced Nero’s face under his left eye, sliced through his trachea and esophagus and passed through his neck into his shoulder, where it remains lodged pending his ability to survive another surgery. In the bedlam of Gannon, 32, being fatally shot in the head Thursday, McClelland said first responders couldn’t locate Nero.

“When this happened, he never got rescued until almost three hours after the incident,” McClelland said. “We knew he was deployed, but we had no idea exactly where he was. He could have taken off up the street. SWAT had to clear the house, check for other shooters, booby traps. … He (Nero) was up in a corner of the attic by himself, just bleeding. It was heartbreaking. When they finally found him, I was waiting outside the house.”

McClelland, who began working with Nero when he was just three months old, recalled with a bittersweet laugh when two years ago he ceded the dog’s leash to Gannon for what he thought was a partnership that would last for years.

“The transition from my house to his house, by the end of the night, it was done,” McClelland said of Nero’s attachment to Gannon. “Sean was a mellow, cerebral guy — and athletic. Just had a way about him. Malinoises can be a bit on the wild side, high-energy. Nero just happened to be on the more mellow end of the spectrum. It was absolutely a great match.”