An Ontario man accused of coercing young girls in Canada and England to expose themselves online has been charged with four additional offences, including sexual assault.

A bail hearing for Mark Bedford, 21, of Kingston was postponed Thursday after Crown prosecutors filed the new charges. Police said the sexual assault victim was a Kingston girl under the age of 18.   

Bedford was also charged Thursday with obtaining graphic images of the same girl, impersonating the girl in order to cause her "disadvantage" and with causing mischief by interfering with her data. Police said the offences occurred in June 2005.

At a news conference last month, police said a man had used the internet to lure and extort pornographic images from more than 100 young girls in Ontario, Alberta and England. They said threats of death and rape had been used to get girls aged nine to 15 to perform sexually in front of their web cams.

The original charges against Bedford were two counts of luring a child with a computer, two counts of possessing child pornography, three counts of making child pornography, two counts of distributing child pornography and three counts of extortion.

The investigation took place from September 2005 to April of this year and involved the Ontario Provincial Police, RCMP, Kingston Police Service and Kent police in the United Kingdom.

Police charged that Bedford hacked into e-mail accounts to access their list of contacts. It is believed he used the screennames Marco1812000 and Supalover666.

Two teenagers in Edmonton were heralded at the news conference in July for helping police break open the case.

Bedford's next court appearance is scheduled for Aug. 16.

with files from Canadian Press