It’s no surprise that Alpharetta police K-9 Mattis appeared on the DC Comics inspired HBO series “The Watchman,” he’s a superhero to his handler Sgt. Mark Tappan.

Wednesday, the 7-year-old German Shepherd retired after nearly six years of service and will continue to live at home with Tappan. And while Mattis will have plenty of days of leisure, Tappan said the beloved dog will help promote a children’s book with him titled, “My Dog Mattis.” The book is currently being illustrated, Tappan said

The 97-pound pooch is accustomed to the spotlight. Last year he appeared on A&E’s “America’s Top Dog” and he’s been featured on such TV programs as “Entertainment Tonight” and “Good Morning America.” His appearances and popularity brought him more than 200,000 followers on Instagram, Twitter and Facebook.

Mattis was born in Slovakia in 2013. Tappan said they met two years later at a kennel in Anniston, Alabama, where Mattis was training.

“There was an instant bond,” Tappan said. “He stood out among the other dogs. He was possessive but stable and level-headed.”

Tappan said that he worked hard to create a bond of trust with Mattis. But Mattis has his own special way of connecting people and bridging gaps between them, he added.

Tappan said he’s leaving the K-9 unit and won’t be working with another K-9.

Mattis assisted police with more than 200 arrests and he and Tappan have raised over $200,000 for charities, police said. CREDIT: Rebecca Wright for the Atlanta Journal-Constitution

Credit: Rebecca Wright

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Credit: Rebecca Wright

Mattis assisted police with more than 200 arrests and he and Tappan have raised over $200,000 for charities, police said.

Following a retirement ceremony Wednesday on the steps of Alpharetta police headquarters, a nostalgic Tappan took Mattis to the site where the K-9 was injured chasing a suspect in 2016.

Five years ago, Mattis jumped over a 30-foot retention wall, landed on the suspect and waited for Tappan to get to him. After Tappan arrived, Mattis chased down a second suspect and when that person surrendered, the dog collapsed, Tappan said.

Mattis suffered a lacerated liver and was rushed to surgery.

Live-streaming a trip down down “memory lane” with Mattis’ 200,000 Instagram followers, teary Tappan said, “I was thinking earlier today how cathartic it is be to just be able to play ball with him.”

In retirement, Mattis will likely also get into some mischief. He was captured on Instagram Wednesday night standing upright over a kitchen counter with flour on his nose and a baker’s rolling pin under his paw.

Sgt. Mark Tappan and retired police K-9 Mattis play in the front yard of Sgt. Tappan’s house in Alpharetta, Georgia, on Friday, March 19, 2021. Mattis, former Alpharetta Police K-9 with a huge following on Instagram, retired this week after joining the service in 2015 and assisting with more than 200 arrests. (Rebecca Wright for the Atlanta Journal-Constitution)

Credit: Rebecca Wright

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Credit: Rebecca Wright