Christopher Nelson, the Caribbean country's director of prosecutions, says a judge ruled Friday that a coroner's inquest must be held before the criminal case can proceed.
But he says the charges can be brought back if evidence presented at the inquest suggests they are warranted.
The officers are accused of beating Oscar Bartholomew, 39, into a fatal coma on Boxing Day 2011 while he was in a cell in the hamlet of St. David's.
Relatives said the altercation occurred after he bear-hugged a plainclothes policewoman he had mistaken for a friend and she yelled, "Rape!"
Bartholomew lived in Toronto but was in his native Grenada to visit family with his wife of 10 years, Dolette Cyr, of Cascapedia-St. Jules, Que.
The Coroner's Act mandates an inquest when someone dies in a public facility, such as a prison, but Nelson says he believes it's the first time the act has taken precedence over criminal proceedings.
"There is no precedent so far as I am aware, certainly not in Grenada," he said in a phone interview Saturday.
"My view is... the coroner's inquest cannot take precedence over the decision of the prosecuting authorities to lay charges when they think it is possible to do so," he said.
"My view is at least they can both run parallel."
Unlike inquests in Canada, those in Grenada can return a verdict of murder or manslaughter, leading to criminal charges.
"The result can be the same but the difference is that with the coroner's inquest, it's the coroner in the driving seat of the process," he said.
"The difference is in the coroner's inquest there are no charges, there are no accused persons, it's just a fact-finding inquiry."
Nelson said his office has yet to see the judge's written decision and will decide whether to appeal after reading the document.
But he said an appeal is likely and could bring a stay of the order quashing the charges.