Image copyright Halifax Regional Police

A woman dubbed the Internet Black Widow was released from prison in Canada on Friday, prompting police to issue a warning to potential victims - elderly men looking for love. What could have earned a sweet-talking 80-year-old such a sinister reputation?

Alex Strategos was lonely and searching for romance when he met Melissa Ann Shepard on an online dating site.

"At first, I thought she seemed very nice," Strategos, now 84, told the BBC from his home in Florida. Shepard drove down from Canada and quickly moved in with Strategos, who described her as a "very classy lady".

But he soon discovered she was less classy than she seemed. "I went to hospital," says Strategos. "She sent me there."

Their relationship was one of many that have resulted in Shepard serving time in prison.

This week she was released after two years, nine months and 10 days in jail for spiking the coffee of a new partner, Fred Weeks, her neighbour in a quiet retirement community in Nova Scotia. According to court documents, she knocked on his door and told him she was lonely, and she'd heard he was lonely too.

The couple had a civil union ceremony in his living room, and although the marriage was reportedly never certified, they went off on honeymoon to Newfoundland. Prosecutors said Shepard gave Weeks heavy doses of sedatives during the journey, leaving him unable to distinguish between the reverse and drive gears in his car, and to start the vehicle when they were disembarking from a ferry.

The next day he needed a wheelchair, could not put on his shoes and did not know where his car keys were, the court heard. But it was not until he was hospitalised after falling out of bed that the drugs were found in his system and police realised something was wrong.

Image copyright AP Image caption Fred Weeks says Melissa Shepard is a "smooth actor"

Image copyright AP Image caption Weeks fell out of bed while drugged at the Chamber's Guest House Bed and Breakfast in Nova Scotia

Shepard was initially charged with attempted murder but later convicted on a lesser charge of "administering a noxious substance".

In an interview with The Canadian Press this month, Weeks said he did not want Shepard to come near him. "She's too smooth an actor," he said. "She kept me in the dark for a long time, telling me her stories... Everything was a lie that she told me."

Strategos believes Shepard drugged him too - by spiking his ice cream. He says she also stole about $20,000 from him during the few weeks they were together. She served five years in a Florida jail after pleading guilty in 2005 to seven charges, including forgery and grand theft from a person aged 65 or older.

Strategos says he knew very little about Shepard when they first met and was unaware of her previous crimes, including her 1992 conviction for killing her second husband, Gordon Stewart.

Journalist Barb McKenna met Shepard soon after she was released from prison for that offence, in 1994. Shepard had served two years of a six-year manslaughter sentence for drugging Stewart and running him over twice in a car. Shepard's defence was that Stewart had been trying to rape her at the time.

Melissa Ann Shepard: A violent history

Image copyright Prisontv.net Image caption In interviews after her release from prison in 1994 , Shepard claimed her late husband had abused her

1977-1991: Serves prison sentences for more than 30 separate convictions for fraud

Serves prison sentences for more than 30 separate convictions for fraud 1992: Convicted of manslaughter over the death of her second husband, Gordon Stewart, who she drugged and ran over twice with a car - she is sentenced to six years in jail but gets parole in 1994

Convicted of manslaughter over the death of her second husband, Gordon Stewart, who she drugged and ran over twice with a car - she is sentenced to six years in jail but gets parole in 1994 1994: Features in a National Film Board documentary, When Women Kill, about victims of domestic abuse who attack their partners

Features in a National Film Board documentary, When Women Kill, about victims of domestic abuse who attack their partners 2002: Her third husband, Robert Friedrich, dies just over a year after the couple meet through an online dating site - no charges are brought against her

Her third husband, Robert Friedrich, dies just over a year after the couple meet through an online dating site - no charges are brought against her 2005: Sentenced to five years in prison in Florida after pleading guilty to seven charges, including forgery and theft from Alex Strategos, who she had met online - Strategos, now 84, says she stole about $20,000 from him and believes she put drugs in his ice cream

Sentenced to five years in prison in Florida after pleading guilty to seven charges, including forgery and theft from Alex Strategos, who she had met online - Strategos, now 84, says she stole about $20,000 from him and believes she put drugs in his ice cream 2013: Jailed for two years, nine months and 10 days in Canada for spiking her new partner's coffee with sedatives

McKenna met Shepard when the former prisoner was giving talks across Canada about battered woman syndrome, a criminal defence that can be used by victims of domestic abuse who go on to attack their partner. She also appeared in a 1994 documentary called When Women Kill, and won a government grant to help others like herself.

However, as McKenna began investigating Shepard's back-story she found some 30 separate convictions for fraud between 1977 and 1991.

"There's a saying, 'She could charm the bark off a tree'," says McKenna.

"She's very slick. You would confront her and she could immediately think up a response to it… even though it was an obvious lie."

In 2001, Shepard married her third husband, Robert Friedrich, just days after meeting him through a Christian dating site. Friedrich died 14 months later at the age of 84, leaving tens of thousands of dollars in assets to his new wife. His sons made a criminal complaint alleging that she killed him by overdosing him with prescription medicine, according to reports. They later won back $15,000, although she was never charged with any crime.

Image copyright AP Image caption Police in Nova Scotia say Shepard, seen here in 2013, is a "high risk offender"

When journalist Barb McKenna heard about the Fred Weeks court case in 2013, she says she was "horrified" at how short Shepard's sentence was.

"My first thought was, what's wrong with the system?" she says. "I suppose people don't expect old ladies to be cold-blooded killers. She presents as this sad, tragic figure - almost someone to be pitied."

Shepard has refused interview requests.

Prosecutors put strict conditions on Shepard's release this week, insisting that she report any relationship with a man, to allow police to inform him "of her history in these and other legal proceedings". They also bar Shepard from going online or even owning any device capable of accessing the internet, and she must allow police to photograph her if she alters her appearance.

Halifax police went to the lengths of issuing a media release advising all citizens that "a high risk offender is residing in our community" and warning that she "has been assessed as being a high risk to re-offend".

Alex Strategos agrees with this assessment.

"I don't think she should be released," he says.

"I don't know what the judge had in his mind. What she was, she still is - she's the black widow. Some guys better watch out, that's all I can say."

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