Tony Reed was taken into custody on Monday in connection with the suspected murder

By Char Adams
Updated May 17, 2016 12:40 PM
Credit: Snohomish County Sheriff's Office

One of two brothers suspected in the presumed murder of a Washington state couple turned himself in to officials on Monday – but the whereabouts of his brother remain unknown, PEOPLE confirms.

U.S. Marshals officials took Tony Clyde Reed, 49, into custody on Monday at the Mexico border after he crossed into the U.S., Snohomish County Sheriff’s Office spokesperson Shari Ireton, confirms to PEOPLE.

Police have been searching for both Reed and his brother, 53-year-old John Blaine Reed, since April in connection with the disappearance and suspected murders of Oso couple Patrick Shunn, 45, and Monique Patenaude, 46.

Reed was booked into San Diego County jail but Ireton says it is unclear whether he will be extradited to Washington.

After naming them as suspects, authorities said the brothers were convicted felons and that they were “armed and dangerous.”

In a previous statement, Snohomish County Sheriff’s officials said that detectives obtained surveillance footage allegedly tying the Reed brothers to “the disposal of Shunn and Patenaude’s vehicles.”

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“Detectives believe the couple were the victims of homicidal violence based on evidence collected at the scene of the missing couple’s vehicles, as well as the former residence of John Reed,” police said in the statement.

An affidavit for a search warrant released in April alleged that John once threatened to shoot the couple over an ongoing property dispute between the neighbors, who share a common driveway.

The alleged tension between the brothers and Shunn and Patenaude reportedly began when the couple cut brush between the two properties. In the affidavit, obtained by The Seattle Times , investigators wrote that John “reportedly stated he would shoot or assault them if they didn’t leave [him alone].”

Shunn and Patenaude were reportedly afraid of John and thus avoided naming him as a defendant in a lawsuit over a property dispute more than two years ago, KOMO reported.

“They weren’t looking forward to any kind of conflict with Mr. Reed,” the couple’s former attorney Thomas Adams told KOMO. “They didn’t want to provoke any kind of an issue with him.”

The whereabouts of the couple remain unknown, police said in a statement.