Workers discovered the remains of Mr Christianos, 40, on July 13 in Oakleigh South while they were cleaning out a storage unit.
He went missing in 2001 and was last seen at a residential home in Bentleigh East.
Born in South Australia, Victoria Police say Mr Christianos had been estranged from his family for some time before he disappeared.
An inquest in 2011 found he likely died on or after June 11, 2001.An inquest in 2011 found he likely died on or after June 11, 2001.
However, the cause of death and the circumstances were unable to be determined.