A criminal investigation has been launched into the emergency medical care provided to a Good Samaritan who police have said was killed after trying to intervene in an altercation earlier this month in Hamilton.

Yosif Al-Hasnawi -- described by police as a brave young man who was trying to do the right thing -- was shot and killed on Dec. 2 after he tried to help an older man who was being accosted by two other men.

The men have since been charged in connection to the death. Dale Burningsky King, 19, was charged with second-degree murder and a 20-year-old was charged with accessory after the fact.

But witnesses to the interaction have criticized Hamilton paramedics and police for not taking Al-Hasnawi seriously when he said he was in pain.

Earlier this month, Tom Raczynski, who lives in the area, said he heard screams that drew him out of his home that night.

"He was lying there complaining he was hurting and they kept saying he was faking," Raczynski said of paramedics and police at the scene.

"The one paramedic kept saying 'oh you're a good actor,"' Raczynski said. "I just thought it was disgusting. Like somebody's shot, you take him in to the hospital, you don't leave him lying there."

On Wednesday, Raczynski said he was appalled by how long it took paramedics to treat Al-Hasnawi.

"That poor kid lied there for an hour and a half," he said.

"This boy could have been alive in my eyes if they would have did it right away."

Niagara Regional police will conduct the investigation, said Hamilton police Const. Jerome Stewart

"The Hamilton Police Service believe a criminal investigation is warranted based on the review of the preliminary evidence," Stewart said in a statement.

A Niagara Regional police spokeswoman said they were asked late last week by Hamilton police to investigate the care given by Hamilton Paramedic Services the night Al-Hasnawi died.

"It's about time," Raczynski said when he heard about the criminal investigation.

Raczynski said Niagara police have yet to contact him, but Hamilton police brought him down to the station for a statement about the paramedics' behaviour about a week and a half ago.

Russell Crocker, deputy chief of the Hamilton Paramedic Service, said two days after the 19-year-old died that the service launched an investigation into the incident as a result of information it received.

A Hamilton paramedic spokeswoman said the service will pause its internal investigation now that a police investigation is underway.