A leading imam in Ottawa says his mosque has seen a higher amount of interested converts to Islam in the months following last year’s shooting at the Canadian Parliament than ever before. What’s troubling Samy Metwally is that the converts, who are mainly young men, never return following the initial meeting, causing him to worry they are seeking a more radicalized version of the faith elsewhere.

“The vast, vast majority of new converts, we have never seen them before and then we never see them again,” Metwally told the National Post. “They disappear and they never come again. This is a big concern. We are concerned about who they are getting information from.”

Metwally explained that potential converts are susceptible to radicalization as they form an understanding of the religion, and can be easily manipulated by alternative sources, including on the Internet. He said he met with each of the 15 to 20 young men who expressed interest in converting and tried to follow up with them, but lost touch and never saw them again.

The jump in potential converts comes after October’s deadly shooting in the city’s Parliament Hill, in which the gunman killed a soldier at the Canadian National War Memorial and later himself. The man, a Muslim convert, was later killed when he entered the national Parliament building.