Raymond Newman was acquitted in 2012 by the province's Supreme Court of second-degree murder in the death of Chrissy Predham-Newman, who was found dead in her St. John's apartment five years earlier.
The province's appeal court ruled in December that the trial judge properly concluded that warrants used to search Newman's car and home were invalid.
The Public Prosecutions Division says it will not seek leave from the Supreme Court of Canada to appeal that ruling.
The division says it made that decision after reviewing case law, legislation and policies on the conduct of criminal prosecutions.
It says it has consulted with Predham-Newman's family and expressed its sympathies to them.