OSO, Wash. – In a clearing 16 kilometres up a gravel logging road, freshly cut hemlock branches cover the root well of a wind-toppled fir. Atop the boughs, a bouquet of red, white and blue carnations left by detectives marks the grim discovery they made here: the shallow grave of a local couple shot to death six weeks ago.

The killings of Patrick Shunn and Monique Patenaude, a native of British Columbia, were a knife-twist of heartache in Oso, a tiny, rural community northeast of Seattle that was devastated in 2014 by the nation’s worst landslide disaster.

The couple lived on 8.5-hectare riverfront spread abutting the scar where the hillside gave way, obliterating three dozen houses and killing 43 people. They shared a gated driveway with suspect John Blaine Reed, 53, who is still at large.

Reed’s younger brother, Tony Clyde Reed, provided information that led detectives to a remote area near the couple’s home where police found their buried remains.

Reed turned himself in last week at the U.S.-Mexico border after a month-long manhunt, police have said.

Each brother is charged with first-degree murder.

The younger Reed has not helped track down his brother, prosecutors say. He sympathized with the victims’ families and offered limited co-operation to investigators, but he insisted he’s innocent of murder, said his attorney, James Kirkham.

“My client is innocent of the first-degree murder charges,” Kirkham said after Tony Reed pleaded not guilty to two counts of first-degree murder and unlawful possession of a firearm. “He’s here to defend himself.”

The older brother was known in the area for threatening officials after the slide.

Snohomish County sheriff’s spokeswoman Shari Ireton said the area where the bodies of Shunn and Patenaude were found was well concealed.

“Our search and rescue folks were searching a 20-plus-square-mile area that’s overgrown and forested with lots of elevation changes,” she said. “I don’t know how they would have found them.”

Carpeted with wild grasses and purple and white foxglove, the clearing is above the landslide, just north of the couple’s home as the crow flies, but a lengthy drive on the area’s network of logging roads. Head-high saplings wave in the breeze, the tips of their branches bright green with spring growth, and older trees tower overhead.

Shunn, 45, and Patenaude, 46, were described as outgoing animal lovers who liked to travel. Shunn, a one-time Army Ranger, was employed at a company that refurbishes aircraft interiors, and Patenaude had worked at an organization that provides services to disabled adults. The couple met at the Burning Man festival in the Nevada desert, relatives said at a memorial service last month.

John Reed’s property was just up the gated gravel drive from Shunn and Patenaude’s home.

In 2013, when Shunn and Patenaude sued two other neighbours over the use of the driveway across their property, they avoided naming him as a defendant because they didn’t want to antagonize him, their former lawyer, Thomas Adams, told The Associated Press.

In court documents, authorities described a constant, ongoing dispute between Reed and the couple.

A former Snohomish County reserve deputy, Bruce Cheek, described John Reed to investigators as loud and aggressive. John Reed was known for threatening to drive his truck through the Oso fire hall after the slide because he wanted his driveway fixed.

The county bought Reed’s house March 30 for about US$246,000 to ease any risks from future flooding related to the landslide. But he was none too happy recently when Patenaude told the county he had been “squatting” there, officials said.

Suzanne Loo, a neighbour, reported Shunn and Patenaude missing April 12 when they failed to respond to messages and their animals went untended. When she was feeding them the next day, she saw the Reeds at the gate and took a picture of John’s red truck as it drove off.

Within days a search crew in a helicopter found their vehicles, a Jeep and a Land Rover, above the landslide. They had been pushed down an embankment and had blood inside, but no bodies.

A medical examiner positively identified the couple’s bodies Thursday.