05/25/2016 07:30 EDT | Updated 05/26/2017 05:12 EDT

Bodies Of Monique Patenaude And Patrick Shunn Believed To Be Found: Police

Monique Patenaude and Patrick Shunn have been missing and presumed killed in Washington state.

EVERETT, Wash. — Police say they found the remains of two people they believed to be a woman and her husband who have been missing for six weeks and presumed killed in Washington state.

Spokeswoman Shari Ireton from the Snohomish County Sheriff's Office said Tony Clyde Reed — one of two brothers charged with the slayings of Monique Patenaude and her husband Patrick Shunn — provided information that led detectives to pinpoint the remote location near the couple's home Tuesday afternoon

Canadian media outlets have reported that the 46-year-old Patenaude once lived in British Columbia.

The bodies were found buried in an area where the couple's vehicles were found by authorities weeks ago, about 80 kilometres northeast of Seattle near the town of Oso.

Tony Reed, left, and his brother John Reed, right, are charged with the slayings of Monique Patenaude and Patrick Shunn.

Ireton says police are waiting for the medical examiner to confirm the identities, but they have reason to believe that they are Shunn and Patenaude.

Reed appeared in Snohomish County Superior Court earlier Tuesday afternoon and entered not guilty pleas to two counts of first-degree murder and unlawful firearm possession in the case.

He turned himself in last week at the U.S.-Mexico border after a month-long manhunt.

His attorney, James Kirkham, helped arrange the surrender.

Couple involved in property dispute with accused

Kirkham told The Daily Herald in Everett, Wash., on Monday that his client turned himself in to answer the allegations against him.

"My client is innocent of the first-degree murder charges,'' the lawyer said. "He's here to defend himself.''

Authorities are still searching for Reed's 53-year-old brother, John Blaine Reed.

John Reed and the couple were former neighbours. Authorities have said Reed, Patenaude and Shunn, 45, had been involved in a property dispute.

An old photo of Patrick Shunn and Monique Patenaude, released by the Snohomish County Sheriff's Office.

Ireton said Tony Reed has been co-operating with detectives.

People were out in the field Tuesday searching for the couple's bodies, she said, as they have done on multiple occasions since the couple was reported missing last month.

Ireton said authorities had searched in the area several times but getting specific information helped them make the discovery.

Brothers believed to have gone to Mexico

Neighbours called police on April 12, saying Patenaude and Shunn's livestock was left unattended.

Shunn was last seen at work in Kirkland, Wash., on April 11, and his wife was seen the same day near their home.

Their vehicles were found in a remote wooded area near Oso two days later.

On April 18, one of the vehicles driven by the Reed brothers was located in Phoenix, and police said the pair was believed to have crossed the border into Mexico.

— With files from The Canadian Press