MONCTON, New Brunswick — Thousands of police officers from across Canada on Tuesday attended the funeral of three Mounties killed by a gunman last week in what was the deadliest attack on Canada’s national police force in nearly a decade.

Pipers and drummers led mourners at the funeral in Moncton, New Brunswick, which was paralyzed by last week’s massive manhunt for 24-year-old Justin Bourque.

Bourque was caught Friday and charged with three murders and two attempted murders.

The three officers from the Royal Canadian Mounted Police were killed Wednesday after responding to a report of a man with firearms. The victims were Constables Fabrice Gevaudan, Douglas Larche and Dave Ross.

“Together, we struggle for answers,” said Canadian Prime Minister Stephen Harper said. “We ask what in God’s name happened here and why. We may never know.”

Members of the RCMP and municipal police forces, as well as correctional officers and U.S. border patrol officers, were among the more than 2,700 who marched.

A beige RCMP Stetson was placed atop each casket at the front of the service. Danny, a police dog that served with Ross, was led inside. The dog whimpered during the funeral ceremony.

Ross’s brother-in-law, Adrian Vander Ploeg, recalled how the officer was making dinner but dropped everything, including leaving the barbecue lid up and the garage door open, to be among the first to respond to a report of a gunman.

“For those closest to Dave, that barbecue left still open says everything about who Dave was and his devotion to those around him,” Vander Ploeg said.

So many people were expected for the funeral that 10 other sites in and around Moncton were set up for mourners to gather.