YARMOUTH (CBS) – Stunned members of the community are visiting the Yarmouth Police Department after a K-9 officer was gunned down in the line of duty Thursday.

Related: Tributes Nationwide For Officer Gannon

Officer Sean Gannon was shot and killed while serving an arrest warrant to Tom Latanowich at a home in Barnstable. Latanowich, who is now charged with murder, was arrested after a long standoff with police.  Gannon’s K-9 Nero is “fighting to stay alive” after he was wounded in the shooting.

Yarmouth Police Officer Sean Gannon. (Photo credit: Yarmouth Police – Facebook)

“This just shouldn’t have happened. But he was protecting us, you know, the thin blue line. He was protecting us and doing his job,” said local resident Dina Dexter.

“It’s just a sad day in the town of Yarmouth,” said Cheryl Davis, who stopped at police headquarters on Friday.

Some residents brought baked goods, others left flowers in honor of Gannon’s sacrifice. The department said it is “overwhelmed” with food donations and instead asked for financial donations to Yarmouth Police Foundation website.

“We feel helpless,” one woman told WBZ-TV. “We’re all sick. We just don’t feel right. It’s the worst.”

Gannon’s cruiser is now parked in front of the Yarmouth Police Department and draped with black-and-purple bunting. By Friday night, mourners covered Gannon’s cruiser in flowers.

Officer Sean Gannon’s police cruiser covered in flowers outside Yarmouth PD (WBZ-TV)

Bailey Cook, who retired from the police force after 30 years on the job in Connecticut, was in town for a hockey tournament when he heard the news of Gannon’s death. Cook has two sons who hope to become police officers.

“It’s a dangerous, dangerous situation. You never know when you’re not going to come home,” said Cook. “We do it every day. Just yesterday at this time the officer was in his car doing his job, looking to get back to his family and something like this happens. It’s terrible.”

Flowers at Yarmouth Police headquarters after Officer Sean Gannon was killed in Barnstable. (Image Credit: Beth Germano/WBZ-TV)

Gorett Sousa, Gannon’s former teacher from Bishop Stang High School in Dartmouth, said he talked often about being a police officer and followed his dream.

“He was very passionate about it and he put his whole soul into that work,” said Sousa.

Gannon was on the Yarmouth force for 8 years. He was the first full-time K9 drug detection officer, and was paired with his K9 partner Nero about a year ago.  The police dog was wounded in the fatal shooting that killed Gannon.

Beyond the job he worked with youth, volunteering with Big Brothers/Big Sisters of Cape Cod and was a fixture in the community with Nero.

Cheryl Shields said Gannon helped her with training advice for her dog, Gunnar.

“He told me, ‘You stay consistent with him,’ and so forth and so on,” Shields said.  “And our paths would cross once in a while and he would ask me how Gunnar was doing.”

Jeanne Kenneally said she knew Gannon’s kindness and his murder hits close to home.

“Our little community’s been rocked by this epidemic of drugs and violence, and here we have one of the outcomes,” she said.

Cook said Latanowich’s lengthy criminal record of 111 prior charges points to an issue that many police officers deal with every day.

“Things fall through the cracks. Mistakes are made. And it ends up somebody losing their life. It’s ridiculous how things are done,” said Cook.

“It’s amazing that something like this could happen to such a young, fine officer. I feel for his family, for the police department, for the citizens of this town.”

WBZ-TV’s Beth Germano contributed to this report.