01/15/2015 16:11 EST | Updated 03/17/2015 05:59 EDT

ISIS suspects known as 'high-risk travellers,' Edmonton police say

Three Edmonton men believed to have been killed while fighting for ISIS had been identified by police as high-risk travellers before the trio left the city in 2013.

Although police knew the men had gone overseas, they were unaware of their apparent deaths until learning of CBC News reports Wednesday, said Deputy Chief Brian Simpson.

CBC reported that MahadHirsi and his two cousins Hamsa and Hersi Kariye were killed while fighting for ISIS, according to Ahmed Hirsi, the father of Mahad. A fourth cousin from Minnesota is also believed to have been killed. 

Simpson said Edmonton police were not specifically investigating the trio.

"EPS, like other services across the country, work through the RCMP, who has a national mandate for any terrorist or extremist activities," he said. "We worked with the RCMP."

Simpson said the cases are among a growing number police have been investigating over the past year and a half.

"A year and a half ago, it would have been a rare thing," he said. "There’s a lot more today."

Son radicalized in city, father says

Ahmed Hirsi believes his son Mahad, 20, was radicalized in Edmonton.

In 2010, Mahad moved from Toronto to live with his aunt in Edmonton, where he finished high school and began working and regularly attending a mosque.

Hirsi said it was during that time that Mahad became very religious and he noticed a change from the respectful, generous boy he had raised.

“Some people, I don’t know who he is, they make him brainwash and they change his mind,” he said.

Mahad eventually moved in with his cousins, Hamsa and Hersi Kariye, who also lived in Edmonton.

Hirsi believes they left together to go overseas in October 2013, but he didn’t even know his son had left the country at that time. He found out when Mahad called his brother from overseas.  

Soon after, Hirsi said, police appeared on his doorstep and showed him a picture of his son. They said he was in Syria and asked if he had a Twitter account.

Hirsi begged police to bring his son home. He believed that even if his son ended up in a Canadian jail, at least he would still be alive.

Then, last October, someone phoned the mother of two of the cousins to tell her the three men had died, as well as a fourth cousin from Minnesota.

One family member insists the men did not go overseas to join ISIS. Hamsa and Hersi Kariye’s brother said the cousins went to Egypt to study their religion.