Toronto police said Tuesday they will be searching a southwestern Ontario landfill for the remains of a 57-year-old man that they believe was the victim of a homicide.

In a news release, police said a search warrant was granted for the Green Lane Landfill in Southwold, about 25 kilometres southwest of London, as part of an investigation into the disappearance of Nathaniel Brettell.

Brettell was last known to be in his home in the area of Westona Street and Dixon Road in Toronto on January 21, but hasn't been seen since, police said.

When officers attended the area in February to search for Brettell, they were allegedly attacked by a man with a butcher knife. Then 33 years old, the man was arrested and charged for several offences, including two counts of attempted murder.

Police say they have not been able to locate Brettell despite "extensive inquiries" and evidence from the scene led investigators to believe his disappearance was a homicide.

In May, the man arrested earlier was subsequently arrested again and charged with second-degree murder.

Police said a "development in the investigation" led them to believe Brettel's body may be at the landfill.

The search will start on July 5 and is expected to continue for the next couple of months.

"Residents in the area of the landfill will be informed of any potential impacts that may result from the search. However, it is not expected to impact garbage collection in Toronto," the news release said.

Anyone with further information is asked to contact police.