A member of the Canadian Armed Forces appeared in court on Thursday facing 18 new charges as part of an expanding sexual assault probe.

Cpl. Derrick Gallagher had been arrested March 31, and then charged with eight counts of sexual assault and two counts of voyeurism just days later 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.

He made a brief court appearance in Pembroke, Ont., via video from the Ottawa-Carleton Detention Centre and his case was adjourned until April 24. That's when he will once again appear via video.

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.‚Äč

All of the alleged incidents happened during his time with the military.

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.

Corrections

  • 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 ET