UPDATE @ 5 p.m.: Police remain on scene on Friday.
An OPP mobile command unit is at the property, along with a Toronto Police Forensics Unit.
The investigation seems to be focused on the back of the property, but no other details have been released.
A police presence continues around a home north of Madoc, connected to a murder investigation in Toronto.
On Thursday, Toronto Police held a media conference to update the investigation under Project Prism.
In April last year, Selim Esen went missing from the area of Young and Bloor streets, while Andrew Kinsman went missing in June near Parliament and Winchester streets, both in Toronto.
Detective Sergeant Hank Idsinga says there are five properties connected to McArthur that have been secured.
Idsinga says it could go further than just the two that went missing from Toronto.
The house that police are watching in Madoc Township, was sold last April, the same month Esen went missing.
In a Facebook post, neighbour Joanne Irvine says McArthur spent time at 2598 Cooper Road in Madoc Township last year and he always seemed to be in the garden. She says it is a large a large piece of property, which is fairly secluded. She says when he (McArthur) began coming to the property last year, the first thing he did was start constructing large gardens. Irvine originally stated he lived there, however, she updates that perhaps someone else owned the property near Eldorado.
She says police set up flood lights Thursday evening and investigators appear to be focusing their attention on the back of the property.
Another neighbour talked to Quinte News and said several homes in the area sold around the same time last year, many to people from Toronto.
Detective Idsinga says if you have any information on the investigation, you can contact Project Prism at (416)808-2021 or Crimestoppers.
CFRB 1010 in Toronto says McArthur next appears in court February 14, 2018
The full statement from Thursday with Detective Sergeant Idsinga is below.