Police officers arrived at the highrise at 85 Fiddlers Green Rd., at about 4:15 p.m. Saturday.
London police Const. Ricardo Juliao told CBC News police received a "death complaint," related to a particular unit in the building.
"In this case, it was just basically an odour that was coming from the unit, which attracted attention and we were subsequently called," he said in a telephone interview Sunday.
Man, 38, facing murder charges
Juliao said police initially found a deceased man in the unit and then found another deceased man after investigating further.
The names of the deceased have not yet been released.
A 38-year-old London man has been arrested and charged with two counts of second-degree murder, as well as a single count of committing an indignity to a human body.
Juliao did not identify what relationship existed between the deceased men and the accused, though he said they were "known to one another."