Crown attorney Diane McGrath said the case involving Melissa Ann Weeks will return to provincial court Tuesday in Sydney, N.S.
McGrath said the Crown will continue to oppose Weeks's release.
"Our concern, first of all, is whether or not she's a flight risk and secondly, the protection of the public," she said in an interview after the brief hearing. "There's nothing at this point that I can see that would satisfy us with respect to those two aspects."
Weeks has also been charged with administering a noxious substance to Fred Weeks, 75, of New Glasgow, N.S. Police say he fell ill at a bed and breakfast in North Sydney last weekend.
Court documents allege her husband was given benzodiazepine with the intent "to endanger the life of Fred Weeks."
The website for the U.S. Department of Justice says benzodiazepines are a class of drugs that produce central nervous system depression and are commonly used to treat insomnia and anxiety.
Weeks was convicted of manslaughter in 1992 in the death of a previous husband who she drugged and ran over twice with a car.
She also has convictions for fraud and forgery involving men she had relationships with.
Weeks was also sentenced in 2005 to five years in prison on seven counts of theft from a man in Florida who she had met online. Alex Strategos, now 81, said she stole $20,000 from him over the month that they lived together.
Over the years, Weeks has been dubbed in some media reports as the "Black Widow" or the "Internet Black Widow."