A Washington state husband and wife who disappeared last week are now believed to have been murdered, and the suspected killers remain on the loose and are considered armed and dangerous, Snohomish County Sheriff Ty Trenary said Sunday.

Detectives on Saturday found two vehicles – a Jeep Wrangler and a Land Rover – belonging to former Army Airborne Ranger Patrick Shunn, 45, and his wife, Monique Patenaude, 46, in a remote, rocky area about 15 miles from the couple’s Arlington home. Trenary said “it’s clear” Shunn and Patenaude are deceased based on evidence collected from those vehicles, and evidence obtained from the couple’s house. Officials have not yet recovered any bodies.

Police are searching for two brothers, convicted felons John Blaine Reed, 53, and Tony Clyde Reed, 49, in connection with the deaths. Trenary said the men were seen on video surveillance disposing of the vehicles that were discovered Saturday. He did not say what crime the men were previously convicted of, but Trenary cautioned anyone who encountered them to avoid the pair.

“They are armed and dangerous and the public should absolutely be worried,” Trenary said.

The men may be driving a 2007 Volkswagen EOS Coupes with Washington license plate AXH5106, but authorities do not know their current location. They had been in the Ellensburg area recently.

John Reed’s house was “very close” to where Shunn and Patenaude lived and it’s believed there was a property dispute of some kind between the parties. John Reed had been intermittently visiting his house, officials believe.

It was known that Shunn and Patenaude had been engaged in a legal dispute with neighbors, accusing the neighbors of assault, trespassing and scratching death threats in the mud, The Seattle Times reported. The neighbors were not named in The Times report and it’s unclear if they were John or Tony Reed.

Shunn sought a restraining order against one of the neighbors, but a court commissioner dismissed the request in January, saying a physical encounter between the two groups appeared to be unintentional.

Shunn and Patenaude were last seen Monday and were reported missing Tuesday afternoon. Their disappearance was instantly considered suspicious because it was unusual for the husband and wife to stay out of contact with family or friends for such a prolonged period of time.

“Pat did not show up for work nor did he call in,” Shunn’s brother, Erik Shunn, wrote on Facebook Tuesday. “That is very uncharacteristic of him. Pat and Monique have pets and livestock and they haven’t been taken care of the last day and a half.”