Hanson's family told Chicago police they'd last seen him Jan. 9 as he left his home in the 6400-block of North Glenwood for work. Police said it appeared Hanson was at his office at some point on the day that he went missing. Family later received a package that had been sent from Key West with Hanson's wallet, identification and other personal items inside.
The relatives contacted Key West Police, who put them in touch with the medical examiner's office. Hanson's body was then identified.
Investigators still do not know how the Chicago man died. An autopsy showed signs of drowning. Toxicology tests are pending.
The Associated Press contributed to this report.