The investigation found that one of the suspects, Robert Hartley, worked for a company that installed a heating system for the couple, and had visited the home several times.
Detectives arrested Hartley and Gourgoulianos last week. Both have been charged with home invasion, first degree assault and theft. Police say Hartley has confessed.
Police are urging residents to keep valuables out of plain view and locked up when workers come into their home.