YARMOUTH, Mass. (WPRI) — Gov. Charlie Baker ceremoniously signed “Nero’s Law” Tuesday, four years after Yarmouth Police Sgt. Sean Gannon and his K-9 partner were shot in the line of duty.

Gannon was killed in 2018 when he and Nero ran into a Barnstable house to serve a warrant. Even though Nero was critically injured, first responders couldn’t treat nor transport him.

Under the new law, which was formally signed back in February, paramedics and medical personnel can tend to K-9s injured in the line of duty, so long as people are prioritized.

“Nero and all K-9 officers like him deserve the same quality of care that we are able to deliver to all law enforcement personnel,” Baker said. “The swift medical treatment and transport now permitted through Nero’s Law will save lives.”

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Gannon’s parents stood behind Baker as he put pen to paper.

“The Gannon family is profoundly grateful to the legislators and veterinary professionals who took the initiative to draft the bill that became ‘Nero’s Law,’ which affords our beloved K-9s who serve us all with unfailing loyalty the expedient care they richly deserve if and when needed,” Denise Gannon said.

The ceremony took place at the Yarmouth Police Department, where Gannon worked for eight years.

“On this sobering 4th anniversary of K-9 Sgt. Sean Gannon’s murder, we are humbled by the signing of Nero’s Law,” Yarmouth Police Chief Frank Frederickson said. “It is legislation that we owe to our fearless K-9s who put themselves in harm’s way for our protection.”

The man who killed Gannon, Thomas Latanowich, was later found guilty of second-degree murder.

Nero has since recovered from his injuries and still lives with the Gannon family.