British authorities are investigating whether a man facing murder charges in Canada — where he has been in custody for two years — may be linked to two additional recent deaths. 

Investigators now suspect Kenneth Law may have supplied as many as 99 people in the U.K. with a toxic salt, or other items used to die by suicide.

CBC News has learned the two recent deaths in Britain occurred this past April and May.

Law, who worked as a cook at a Toronto hotel, was arrested by Peel Regional Police at his Mississauga, Ont., home in May 2023. He has been in custody ever since. 

He is charged with 14 counts of first-degree murder and 14 counts of counselling or aiding suicide in connection with 14 deaths in Ontario. Authorities have called it one of the largest murder cases ever prosecuted in the province.

Law's lawyer Matthew Gourlay has said his client will plead not guilty when his trial begins in January.

WATCH | Police sought to intercept packages sent by Law:

Police tried to intercept packages sent by accused poison seller Kenneth Law

Documents obtained by CBC News lay out how police tried to intercept packages believed to be sent by Kenneth Law and containing a chemical used by vulnerable people as a poison to kill themselves.

Police say Law, 59, ran websites selling a legal — but potentially lethal — chemical, and other suicide paraphernalia, to at-risk clients around the world. Investigators say Law sent some 1,200 packages to buyers in 40 countries before his websites were shut down.

Canadian authorities alerted Interpol to the potentially dangerous parcels in the spring of 2023 after Britain's Times of London first reported on Law's online sales. Officers carried out wellness checks on buyers in several countries, while Peel police sought to intercept packages already in the mail.

The addition of two further deaths in the U.K. this year raises the prospect that authorities did not manage to seize all the parcels shipped by Law before his arrest. 

Britain's National Crime Agency said in a statement Wednesday it's exploring "all viable leads linked to these websites and a Canadian suspect in order to identify evidence of crimes committed in the U.K."

Before his arrest, Law told CBC News the allegations against him are "false."

"This has been a very distressing experience," he said.

A CBC News investigation has found Law's products may be linked to 133 deaths worldwide, including in the U.S., Ireland, Italy, Switzerland, New Zealand and multiple Canadian provinces.

The criminal charges stem from deaths across Ontario, including that of a 16-year-old whose identity is covered by a publication because they were a minor.

The families of 18-year-old Jeshennia Bedoya Lopez, 19-year-old Ashtyn Prosser, and Stephen Mitchell Jr., 21, have all identified their loved ones as alleged victims in the case.

Charges could be 'impossible' to prosecute

The murder charges laid against Law appear to hinge on a separate case before the Supreme Court of Canada. The top court is reviewing a ruling by Ontario's Court of Appeal which deals with the interplay between murder and assisted suicide.

That ruling — involving a nurse who injected insulin into herself, her mother and her daughter — suggests a person may only be liable for murder if they both provided a person who died by suicide with the lethal substance but also "overbore the victim's freewill in choosing suicide."

Ontario Crown lawyers argue that standard, which they contend shifts focus onto the victim's intent from the accused's actions, may make it practically "impossible" to prosecute cases where the victim dies, since their intent may be unknowable.

Law's lawyer said the matter shows the case against his client is "not legally viable."

A decision from the Supreme Court of Canada is expected in the coming months.