Harry Fleischmann, Jr., 35, will be sentenced in Riverhead to 18 years in prison.
As a persistent felony offender, Fleischmann will be behind bars for 15 years for the burglary and three more years consecutively for setting fire to the victim's East Patchogue home to destroy the evidence of the break-in.
"The homeowner, Eric Carver, is an Air National Guard reservist and was on active duty serving in Africa when the defendant committed these crimes," Suffolk County District Attorney Tom Spota said.
Detectives assigned to the Suffolk County Police Pattern Crimes Unit arrested Fleischmann on January 16.
"On December 26, 2012, Fleischmann, using a key he stole from the vehicle of a person watching Trooper Carver's home while he was overseas, burglarized Carver's house, taking credit cards, and then returned to the home the next day to thoroughly ransack the premises," Spota said.
The property taken in the second break-in included Carver's personal, off duty, .9-mm semiautomatic pistol, a generator and his SUV parked in the driveway.
"Fleischmann took a can of gasoline from the backyard shed, poured the gas throughout the house, and set it ablaze, destroying most of house," Spota said.
Fleischmann, who committed these crimes while on parole, has a criminal history dating back to 1996.