May 24 (Reuters) - Two bodies believed to be the remains of a Washington state couple missing and presumed slain since last month were found buried in a shallow grave on Tuesday as one of two suspected killers in the case pleaded not guilty to murder charges.
Information furnished by Tony Clyde Reed, 49, arrested more than a week ago at the U.S.-Mexico border in San Diego, helped authorities pinpoint the location of the makeshift burial site, said Shari Ireton, spokeswoman for the sheriff's office in Snohomish County, Washington.
Reed, jailed on $5 million bond, pleaded not guilty on Tuesday to two counts of murder and one count of unlawful possession of a firearm. His brother, John Reed, 53, remained a fugitive and may still be in Mexico, Ireton said.
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The two siblings are suspected of killing Patrick Shunn, 45, and Monique Patenaude, 46, a married couple reported missing on April 12 by friends in the foothills of the Cascade mountains, about 60 miles (97 km) northeast of Seattle.
John Reed was a neighbor of the couple in the Oso area, which was hit by a deadly mudslide in March 2014, and Shunn had reported to police that he and his wife had been threatened by Reed in a property dispute.
Based on evidence uncovered in the initial search for the couple, detectives concluded they were victims of foul play, but more than a month passed without any sign of their bodies.
Ireton said the remains of a man and woman were finally discovered in a remote, wooded area a few miles (km) north of the couple's home and near the spot where their two cars were found abandoned in April.
Authorities believe the bodies, which were buried together, are those of Shunn and Patenaude, though medical examiners have yet to positively identify the remains, or to determine the cause and manner of the death, Ireton said.
Sheriff's investigators said the Reed brothers both fled to Mexico following the couple's disappearance. The younger brother turned himself over to U.S. marshals at the border on May 16 and was extradited back to Washington.