Authorities have found a .22 rifle in Crescent City they believe was used to kill Brookings couple Edward and Dorothy Hoenshell.

The discovery of the weapon on Thursday has led authorities to consider the couples grandson, Gregory Hoenshell, 21, a prime suspect in the murders.

This is a major break in the investigation and elevates Gregory Hoenshell from person of interest to the prime suspect, Brookings Police Detective John Bishop said Friday.

Finding the gun is the first tangible evidence that confirms witnesses statements about Mr. Hoenshell, Bishop said. Up until now we didnt have any physical evidence.

Bishop and Curry County District Attorney Charles Steak declined to say exactly how or where the rifle was found in Crescent City. Hoenshell is currently in Del Norte County Jail after being sentenced to state prison on unrelated charges in that county.

Steak said detectives from the Brookings Police Department, Oregon State Police and the sheriffs departments in Curry and Del Norte County have been working almost around the clock on the couples murder case.

Most of the investigation has occurred in Del Norte County, where officers followed a trail of clues and information to find the weapon, he said.

The rifle was immediately taken to the Oregon State Police Crime Lab in Coos Bay for testing, Steak said.

Investigators also are waiting for the results of testing on other evidence to come back from the lab, Bishop said.

Before finding the rifle, Curry and Del Norte county authorities searched the Smith River on Thursday for the weapon with no luck.

We got a tip (Wednesday) night that the gun weve been looking for was thrown into the river. The tip said it was thrown off the middle of the Dr. Fine Bridge, said Curry County Sheriffs Detective David Gardiner.

Previously, divers with the Curry County Sheriffs Search and Rescue searched portions of the Winchuck and Chetco rivers.

Police believed Gregory Hoenshell travelled back and forth between Brookings and Crescent City before and after the double murder, Bishop said.

The bodies of Dorothy Hoenshell, 72, and Edward Hoenshell, 77, were discovered on April 9 by a real estate agent entering their home at 717 Fourth St.

The couples car was found in Crescent City by the California Highway Patrol later that day.

Gregory Hoenshell was arrested the following day in Crescent City on unrelated charges.

Hoenshell was sentenced last week in Del Norte County Superior Court to 16 months in a California state prison for possessing a forged check and for failure to appear.

Steak said the investigation into the couples murders is continuing. Anyone with information should contact Det. John Bishop at (541) 469-3118 or call the Crime Stoppers hotline at (888) 974-0000, or the Del Norte County Sheriffs Department at (707) 464-4191.