A Northern Ontario man has been arrested and charged in connection with the murders of three homeless men in downtown Winnipeg.

John Paul Ostamas, 39, has been charged with two counts of first-degree murder and one count of second-degree murder, police said.

Ostamas, who is from a First Nation near Thunder Bay, Ont., and the three victims are all believed to be members of the city’s homeless community.

Winnipeg Police Supt. Danny Smyth described Ostamas as "very transient" at a news conference Tuesday.

"He has spent time in Winnipeg on and off for the last 10 years," Smyth said.

Police say Donald Collins, 65, and Stony Bushie, 48, were found dead less than a block apart on Saturday in downtown Winnipeg. Earlier this month, 37-year-old Myles Monias died after he was attacked at a bus shelter on April 10.

Smyth said the suspect allegedly lured Collins into an alleyway, attacked him and "left him for dead." Hours later, the suspect allegedly led Bushie to a parkade and "attacked and murdered Bushie and left him for dead."

Police believe that Ostamas knew Collins and Bushie.

"I wouldn't say they were friends," Smyth said. "There is no motive that I'm aware of."

Smyth said the suspect encountered Monias by chance early on the morning on Apr. 10 and attacked him at a bus shelter. "He, too, was left for dead."

Ostamas has yet to appear in court to face the charges.

Ostamas's only run-in with Winnipeg Police dates back to a domestic assault charge last March, but Smyth said he has a "violent record," including multiple assaults in the Thunder Bay, Ont. area, dating back to 2002.

Police are checking to determine whether Ostamas should be considered a suspect in crimes in other jurisdictions as well.

Ostamas's brother, Richard, told CTV Winnipeg that he worried about his brother’s mental health and would often tell him to seek help.

"I was always worried about him doing something bad or someone doing something bad to him," Richard Ostamas said.

He added his family was shocked to learn of the accusations and feels bad for the families of those killed.

"I don't know what to say right now; just that I'm his brother and I cared for him," he said. "I wish things didn't turn out the way they did."

Following the homicides, Winnipeg police released surveillance footage of a "person of interest," who turned out to be Ostamas.

Ostamas appears to have posted three messages on Facebook on Apr. 26, after the second and third alleged killings. The most recent post simply reads "the crime familia," while the other two talk about the difficulties of life.

"You gonna be a sheep or a wolf," he says in one lengthy post. The post ends with a Facebook emoticon that says "feeling determined."

Many in Winnipeg's homeless community were left afraid and saddened by the weekend slayings.

"For the past few days, most of my friends, I could see them with tears in their eyes," Kirby Boucher told CTV Winnipeg.

On Saturday, Police advised street people to take caution and avoid being alone.

While Ostamas's arrest did bring some relief, Lisa Goss, the executive director of The Main Street Project shelter, told The Canadian Press that the feeling is temporary.

"The reality is, they're prepared for this every day," Goss said. "It's a different way of life when you don't have the securities that you and I do," she said.

Martin Owens grew up with Bushie on the Little Grand Rapids First Nation northeast of Winnipeg.

"He was always a happy kind of guy, always joking around," said Owens, chief of the First Nation. "He would come out (to Winnipeg) and hang out with his friends and then go home. He just wanted to see his friends again.

Owens told The Canadian Press that Bushie spent his winters on the reserve and had travelled to Winnipeg two weeks ago.

He added that Bushie loved hunting and fishing, and that his mother, who died roughly 10 years ago, taught him to live off the land.

Bushie is survived by an older brother and sister.

"I don't even know how to describe it – he will be missed," said Owens.

With files from The Canadian Press and CTV Winnipeg's Sheila North Wilson