Police say an officer who was shot in the abdomen at a Brampton courthouse Friday morning is a "good man and a good officer" and that he is in stable condition in hospital.

Ontario's Special Investigations Unit said Friday afternoon that a man was shot dead by police after he opened fire and "reportedly" wounded the Peel Regional police constable. At a news conference Friday afternoon, a spokesperson with Peel police dismissed rumours that police were searching for a second suspect.

The suspect fired a gun after he walked into the A. Grenville and William Davis Courthouse at about 11 a.m., leading to an "interaction" with police officers, according to a news release from the SIU.

During that "interaction," the man was fatally shot by a Peel Region officer who returned fire, said the SIU, which has taken over the investigation.

The shooting occurred near the front entrance, which has a security checkpoint that visitors must pass through and a separate entrance for lawyers.

A witness told CP24 reporter Cam Woolley the suspect stormed through the lawyers' entrance and was challenged by a male police officer.

The suspect pulled out a gun and opened fire, and a police officer returned fire, the witness said.

The injured officer, who has been identified as Mike Klarenbeek, was clutching his chest after the hail of bullets, the witness said.

Within minutes, additional officers descended upon the scene and a heavily-armed tactical unit arrived in an armoured vehicle to conduct a sweep of the Hurontario Street courthouse, located south of Steeles Avenue.

The injured officer was brought out of the locked-down building on a stretcher, as a fellow officer appeared to be applying pressure to his mid-section, and he was rushed to a trauma centre by paramedics, who were escorted by several police vehicles on the emergency run.

Witnesses describe gunshots

Alex Anderson said he was in a first-floor hallway when he heard a single gunshot that caused people to freeze in their tracks.

"Then a series of shots that just went two, three, four, five. In that process, people were running. Everyone was scattering to the nearest courtroom that they can just get into,” Anderson, 22, told The Canadian Press.

He said he later re-entered the hallway and saw what appeared to be a covered body lying on the floor near the front entrance.

He also saw a woman, who was crying as she spoke on a cellphone, saying she had seen what happened.

"She said that it happened right in front of her, that a man had reached into his long trench coat and fired a shot," Anderson said.

Another witness told reporters he heard four or five gunshots that sent a panic through the immediate vicinity.

“Everyone ducked and we just all took off,” the man said outside the courthouse, which is located across the street from the Peel Regional Police headquarters.

He said the gunshots sounded like firecrackers.

“I don’t know how close it was but my ears were ringing when it happened,” he said. "I couldn't believe how fast the cops got here."

At least one group of students was observing legal proceedings as part of a school field trip. Their teacher told CP24 the group ran out of the building when they heard the gunfire.

Lawyers heard gunshots

Within moments of the incident, lawyers who were in the courthouse sent tweets saying they had heard multiple gunshots.

"Shots fired on the first floor of the courthouse. Locked in a courtroom as the cops clear the building," criminal lawyer Will Jaksa wrote in a message to his Twitter followers, as the situation unfolded.

Sangeeta Patel, a criminal lawyer who was in a second-floor courtroom, did not hear the gunshots but was told as many as four gunshots were heard on the first floor.

Patel said people in courtrooms were ordered to lock the doors and remain inside.

An announcement informed people that one or two people had been injured in a shooting, but no information was provided about a suspect or suspects, Patel told CP24 by telephone from a locked-down courtroom.

About an hour later, Patel said people were allowed to leave the courtroom but police ordered them to stay on the second floor and not to leave the building.

Police cleared the courthouse and began to allow people to leave at about 1:30 p.m.

Meanwhile, the SIU is asking people to call investigators at 416-622-1886 or 1-800-787-8529 ext. 1886 if they have not been interviewed or if they have information about the incident.

The SIU is an arm's-length agency that probes incidents or reports involving police where there has been a serious injury, death or allegations of sexual assault.

With files from The Canadian Press.

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