A Dedham cop was arrested and placed on leave yesterday after he was charged as an accessory in the kidnapping of an Avon man who is presumed dead, authorities said.

Michael Schoener, 40, pleaded not guilty to a charge of accessory before the fact of kidnapping. He was held on $5,000 cash bail and ordered to be placed on a GPS tracking bracelet if he is released, Norfolk District Attorney Michael W. Morrissey said in a statement.

Schoener was indicted for his role in the mysterious disappearance of James Robertson, an Avon man who vanished on New Year’s Day.

James Feeney, 44, has already been charged with kidnapping Robertson and is behind bars on $500,000 bail, authorities said.

Prosecutors said Schoener gave Feeney, the kidnapping plot’s mastermind, a photograph of Robertson, a printout of Robertson’s criminal record, as well as his police badge, handcuffs and an empty pistol holster.

“Robertson, who was on probation, was last seen on January 1, 2014, when two individuals posing as constables came to his home in Avon and kidnapped him under the guise of Robertson having to be drug tested by probation,” Morrissey said in a statement. Robertson has not been seen “since that January 1, 2014, encounter and is presumed dead.”

Dedham police said Schoener was arrested on a warrant issued by a Norfolk Superior Court grand jury. He has been placed on leave, but police did not specify whether it was paid or unpaid leave.

“There are ongoing criminal and internal investigations under way,” police said in a statement.

Dedham police Chief Michael D’Entremont did not return a call for comment.

At the time of the disappearance, state police said Robertson was last seen getting into a silver Toyota Camry.

State police issued sketches of two men thought to have information about the disappearance, and in May, Feeney and another man were arrested.