A second sheriff’s deputy died following a bloody, 13-hour standoff in North Carolina that also claimed three other lives — including the gunman, authorities said Thursday.

Watauga County Sheriff Len Hagaman said the two deputies were “ambushed” as they arrived at a home in Boone shortly before 10 a.m. Wednesday for what was supposed to be a welfare check, Fox News said in a report.

County K-9 Deputy Logan Fox was shot and died at the scene, while a second officer, Sgt. Chris Ward, died after being flown by helicopter to Johnson City Medical Center, officials said.

Hagaman did not identify the two other people killed along with the gunman but said another law enforcement officer, a Boone police officer, was shot in the head but saved by his helmet.

Officials did say that the dead civilians are a stepfather, mother, and her son — but did not specify who among them is the suspected shooter, Fox said.

In a statement on Twitter Thursday morning, the FBI office in Charlotte expressed its remorse over the fatal shootings.

“Our hearts are broken for our law enforcement partners at the Watauga County Sheriff’s Office,” the post said. “There are no words to explain the sorrow the #FBI family feels for you. We continue to be thankful for the men and women who put themselves in harm’s way to protect our communities.”

Deputies sustained gunshot wounds when they arrived at the home around 9:45 a.m., officials said. The standoff with the shooter dragged on all day and did not end until shortly before 11 p.m. Wednesday.