Police have arrested a suspect in the Moncton shootings that left three Mounties dead, wounded two others and kept much of the city’s residents locked in their homes for more than 24 hours.

After a manhunt that stretched into a second night, police said a suspect was finally arrested.

Twitter user Michelle Thibodeau posted a first-hand account of the arrest, saying: “He was in my backyard. I saw him arrested in front of my eyes. He is alive. Thank you #RCMPNB.”

Thibodeau later spoke to CTV News and described how armed officers had suddenly stormed into her backyard.

“They were screaming, ‘Come out with your hands up!’” she said. “Without anything else, he just came out and said, ‘I’m done.’ And he had his arms raised.”

Police earlier identified the suspect as 24-year-old Justin Bourque.

A press conference on the arrest is expected at 7 a.m. ET / 8 a.m. AT on Friday.

As the shootings unfolded Wednesday evening, the suspect had been photographed wearing camouflage and carrying what appeared to be two rifles.

Police had warned people in the northern Moncton area to stay inside and lock their doors, as a small army of officers, tactical team members and police dogs conducted a ground search.

A police helicopter had also been deployed in the manhunt, and officers from across the province had arrived to assist.

RCMP Supt. Marlene Snowman said the suspect was not known to police.

‘Darkest day’

Police are calling Wednesday the "darkest day" in the RCMP's history in New Brunswick.

"This is working through your worst nightmare," New Brunswick RCMP Commanding Officer Roger Brown told a news conference Thursday morning.

Speaking of the families of the deceased officers, Brown said, "there's no way to describe the level of hurt."

CTV News has confirmed the identity of one of the three killed RCMP officers as Const. Dave Ross.

One of the two injured Mounties has been released from hospital, RCMP Cpl. Chantal Farrah told reporters Thursday afternoon, but the other remains under care.

Eyewitness accounts

Shortly after the shootings took place, photographer Daniel St. Louis arrived to the scene. Initially didn't think much of a stopped police vehicle he had come across, until he noticed the side windows had been blown out and there was blood at the scene.

St. Louis then came across a second police vehicle that had four bullet holes in the windshield before spotting one of the officers who had been shot.

"I chose to get a little closer, and that's when I saw that there was blood and a serious injury to the head," he said. "That was more than I needed to see, and it was time for me to leave."

Heidi James, meanwhile, said she was at home with her husband and young children when they first heard gunfire.

"I heard probably about four to five shots. They sounded quite loud," James said, describing how she scrambled to move her children away from the windows as worried friends and relatives began texting her to make sure they were safe.

She said her husband peeked out the window and saw a body, covered with a blanket, next to a "shot-out" vehicle.

Prayers and condolences

News that three RCMP officers died and another two suffered non-life-threatening injuries has prompted an outpouring of messages of sympathy.

Speaking from the G7 meeting in Brussels on Thursday, Prime Minister Stephen Harper said the Mounties' deaths are a reminder that men and women in law enforcement "put their lives on the line every day to protect and serve Canadians."

Harper said his thoughts and prayers are with the families of those killed and wounded in the "terrible incident."

New Brunswick Premier David Alward said it’s impossible to understand the reasons behind the shooting.

"It was very important to reflect on the incredible work, the courage, and the determination of our emergency providers in our province," he said.

Gov. Gen. David Johnston said in a statement that this was a day to remember the sacrifices of the three Mounties killed in the shooting.

"Those who wear the colours of the RCMP understand the risks that come with the uniform, but always defend our communities with bravery and courage," he said.

According to the RCMP Honour Roll page online, the last Mountie shot dead in the line of duty was Const. Douglas Scott. He died after responding to a call on Nov. 5, 2007.

With files from CTV News and The Canadian Press