04/17/2014 08:51 EDT | Updated 06/17/2014 05:59 EDT

Cpl. Derrick Gallagher Faces 18 New Charges In Sex Assault Probe

A member of the Canadian Armed Forces is facing 18 new charges as part of an expanding sexual assault probe.

Cpl. Derrick Gallagher had been arrested March 31, and charged with eight counts of sexual assault and two counts of voyeurism in relation to alleged incidents dating back to 2007.

An Ontario Provincial Police investigation began March 29 after a woman complained to them, police said. That week, their evidence led them to eight alleged victims in the town of Petawawa, Ont.

On Thursday, Gallagher was charged with eight more counts of sexual assault, nine more counts of voyeurism and one count of assault.

OPP said they know of 18 victims and are still trying to identify 50 other women they believe are victims.

They said those women, who may have been drugged and do not know whether or not they were assaulted, could be anywhere in the country.

Police said more women from both Ontario and Quebec came forward after the initial charges were announced, and they're asking anyone else with information to contact them at 613-735-0188.

The 31-year-old infantryman with the 1st Battalion Royal Canadian Regiment joined the military in December 2005, and served in Afghanistan from September 2008 to April 2009.

He is expected to appear in a Pembroke, Ont., courthouse via video link around 1 p.m. ET Thursday.

Correction : An initial version of this story stated incorrectly that Gallagher appeared in court via video link on Thursday morning. In fact, he is due to appear via video link on Thursday afternoon.(Apr 17, 2014 10:15 AM)

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