Officers found John Paul Duffy’s body in a flat in Coatbridge’s Coates Street on Sunday, and a 46-year-old man has since been arrested in connection with the death.
As part of their investigation on Tuesday, officers attended a property in Calder Street, around a mile from where the 51-year-old was found two days before, where they discovered the body of a woman.
Detective Chief Inspector Graham Grant said: “The deaths are being treated as linked and officers are currently carrying out extensive inquiries into both incidents.”
The death of the woman is currently being treated as unexplained and formal identification has not yet taken place, Police Scotland said.
The force said there was an increased police presence in the area as its investigation continues.
Mr Grant said: “We are keen to speak to anyone who may have seen or spoken with Mr Duffy in the days before his body was found, including anyone who may have visited his flat.
“We are also carrying out inquiries to establish places or persons Mr Duffy visited or frequented in the days before his death.”
Police Scotland said anyone with information should contact them on 101, quoting incident number 2360 of Sunday.