Erin Breen said Tuesday that RCMP told the family of Don Dunphy that forensic results won't be provided until after Aug. 15.
She says more work will be required after that, which could push the release of police conclusions into the fall.
Dunphy, 59, was killed by an unnamed Royal Newfoundland Constabulary officer investigating perceived threats against provincial politicians on Twitter.
RCMP say a loaded .22-calibre rifle was seized from Dunphy's home in Mitchells Brook, southwest of St. John's, where he was shot Easter Sunday.
The Mounties say the officer told investigators Dunphy threatened him with a long-barrel firearm before he killed him.
Premier Paul Davis has fended off calls from opposition critics for a public inquiry, saying the RCMP should finish its work first.
The Dunphy family wants a public inquiry after a police investigation and has also called for the RCMP to be replaced with a police force from outside the province.
An RCMP spokesman could not be immediately reached for comment.