The suspect in Monday’s attack on two soldiers in Quebec was arrested last summer when he tried to leave the country, but the RCMP did not have enough evidence to charge him with any crime.

The Mounties also revealed Tuesday that they met with 25-year-old Martin Couture-Rouleau as recently as Oct. 9 in their ongoing attempts to de-radicalize him.

Supt. Martine Fontaine, who heads national security for the RCMP in Quebec, told a news conference Tuesday afternoon that Couture-Rouleau was arrested in July when he attempted to fly to Turkey, but was released because there was not enough evidence to prove he was planning to fight alongside terrorists overseas.

There was also no evidence that Couture-Rouleau was planning an attack within Canada, Fontaine said.

She said Couture-Rouleau’s passport was seized and the RCMP made contact with his family and the imam of a mosque he attended in an attempt to curb his radicalization process.

Fontaine said the RCMP hoped to exert a “positive influence” on Couture-Rouleau through the imam and family members. When police met with Couture-Rouleau on Oct. 9, he suggested that he wanted to take steps to change his life, Fontaine said.

That meeting ended on a positive note and the RCMP had no indication that an attack was being planned, she said.

But on Monday morning, less than two weeks later, Couture-Rouleau allegedly struck two members of the Canadian Armed Forces with his car in St-Jean-sur-Richelieu, about 50 kilometres southeast of Montreal. Couture-Rouleau was subsequently shot and killed by police.

The incident occurred in a strip mall parking lot around 11:30 a.m. One of the soldiers, 53-year-old Patrice Vincent, later died of his injuries, while the other soldier suffered minor injuries.

A local patrol officer witnessed the hit-and-run and gave chase as Couture-Rouleau fled in his car.

Police said Tuesday that Couture-Rouleau called 911 after the attack to claim responsibility for it.

After a four-kilometre chase, Couture-Rouleau’s car rolled into a ditch. Police said he exited the car and lunged at an officer with a knife before he was fatally shot.

Public Safety Minister Steven Blaney said Tuesday that the hit-and-run was “linked to terrorist ideology.”

The Department of National Defence said that Vincent, the deceased soldier, was a warrant officer and a member of the regular armed forces since 1986. He had also worked as a firefighter in a number of cities, including Halifax, Edmonton and Montreal.

RCMP Commissioner Bob Paulson confirmed Tuesday that the suspect is one of 90 suspected extremists on Canadian soil that the force was monitoring. He also confirmed reports that the Mounties had seized his passport.

“He was part of our investigative efforts to try and identify those people who might commit a criminal act travelling abroad for terrorist purposes,” Paulson told reporters following an appearance at the House procedure committee.

Investigators were monitoring him, “along with other suspects,” he said.

Asked whether military personnel in the town are in danger, Paulson replied: “That’s a larger issue that will be informed by a full investigation, and we have to get on that.”

Chief of Defence Staff General Tom Lawson said in a statement that the “safety and well-being of Canadian Armed Forces members is a primary concern.

“Security measures are in place at every Canadian Armed Forces installation across Canada.”

Security has already been tightened on military bases across the country and sources tell CTV News that a number of other options are being considered to protect the troops at home. That could include telling soldiers not to wear their uniforms in public.

Blaney told reporters earlier Tuesday that he is “horrified” by the incident, which he called “a terrible act of violence against our country, against our military, against our values.”

His office later confirmed that Canada has raised the domestic terror threat level from low to medium, in response to “general chatter” from “radical” organizations such as ISIS and al Qaeda.

“This increase is not the result of a specific threat,” a spokesperson for Blaney said.

In a statement issued Tuesday morning, Prime Minister Stephen Harper extended his and his wife’s “deepest condolences” to the family and friends of the deceased soldier, and offered “prayers for the recovery” of the one who was injured.

“I want to express that the authorities can count on our full support in order to get to the bottom of this terrible act,” the prime minister said.

‘Radical thoughts’

The RCMP said Tuesday they began their investigation into Couture-Rouleau in June, after posts on his Facebook page suggested that he was “radicalized to the idea of travelling overseas.”

When Couture-Rouleau was arrested in July, police did not have enough evidence to keep him in custody. Fontaine said investigators presented the evidence to the Crown, which determined that wasn’t enough to charge Couture-Rouleau with any crime.

Although Couture-Rouleau’s passport was seized, Fontaine said there was little else police could do.

“We could not arrest someone for having radical thoughts,” she said.

Fontaine said the RCMP did not continue to monitor Couture-Rouleau after their Oct. 9 meeting, but were still in contact with his family members, who had noticed “changes” in the suspect and wanted to help him.

She also said there was no indication that Couture-Rouleau was planning to use his car as a weapon.

“It would have been very difficult to prevent that … because it’s not a crime either to drive a car or be in a parking lot.”

Couture-Rouleau’s father refused to talk to reporters in front of his home Tuesday, saying he wanted to mourn his son in private.

With reports from CTV’s Montreal Bureau Chief Genevieve Beauchemin and CTV’s Deputy Ottawa Bureau Chief Laurie Graham