Jefferson County, MS Sheriff's Office via FacebookBY: IVAN PEREIRA, ABC NEWS

(NEW YORK) -- Three men have been arrested in connection with the murder of a Mississippi Highway Patrol officer while he was moonlighting as a postal worker.

Lt. Troy Morris, 58, was working his second job for the USPS and driving a postal truck early Friday morning when he called highway patrol and the Jefferson County Sheriff's Office to notify them of a flat tire, police said.

"We dispatched a deputy who arrived a short time later and found Mr. Morris had been shot to death inside his truck,” Jefferson County Sheriff James Bailey told reporters.

Morris had been a 27-year veteran with the force, according to the Mississippi Bureau of Investigation. Sean Tindell, the Mississippi Public Safety Commissioner said in a statement he was in contact with Morris's family and they have received an outpouring of support from around the state including Gov. Tate Reeves.

On Saturday, Treyon Washington, 24, Damion Whittley, 25, and Cdarrius Norman, 17, were arrested and charged with murder in connection to Morris' death.

Washington was arrested in Jefferson County while Whittley and Norman were taken into custody in New Orleans.

There were no signs of theft from the truck, according to investigators. Norman and Whittley are awaiting extradition back to Mississippi, investigators said.

The investigation is ongoing, according to investigators.

"While we are pleased with the progress of this investigation, we realize there is much work left to be done," Col. Randy Ginn of the Mississippi Highway Safety Patrol said in a statement.

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