Forensic anthropologist professor Kathy Gruspier, second from left, walks with police officers at a property where alleged serial killer Bruce McArthur worked, Thursday, Feb. 8, 2018 in Toronto. Toronto police say they've recovered the remains of at least 6 people from a property connected to alleged serial killer Bruce McArthur. (Photo: Chris Young/The Canadian Press via AP)

Bruce McArthur, a 66-year-old landscaper in Toronto, was arrested and charged with the murders of two missing men on Jan. 18.

Eleven days later, he was charged with three more deaths, bringing the total count to five. The suspected serial killings expanded the Canadian investigation dramatically in the ensuing days.

Since then, investigators are examining hundreds of missing persons cases in and around the country’s largest city—and attempting to dig in the frozen earth and flowerpots on dozens of properties where McArthur worked.

The massive undertaking resulted in the recovery of six persons’ remains on a property connected to McArthur, authorities announced Thursday.

Only one previously-identified victim was part of the remains uncovered so far at the property, where McArthur reportedly stored items in exchange to doing landscaping maintenance, according to authorities. A large part of the lawn of the property is being excavated, and police have set up tents and heaters on the property, and brought in a forensic anthropologist to assist in assessing whatever may potentially lay beneath.

This combo of photos provided by the Toronto Police Service shows the five men Toronto landscaper Bruce McArthur is accused of killing, from left to right; Selim Essen, 44, Sorush Mahmudi, 50, Dean Lisowick, Andrew Kinsman, 49, and Majeed Kayhan, 58. Police said on Thursday, Feb. 8, 2018, that they recovered the remains of at least six people from planters on the property which is connected to McArthur. A Toronto detective said the remains, found on property McArthur used as storage in exchange for doing the landscaping, included some from one of the five men McArthur is already charged with killing, Andrew Kinsman. (Credit: Toronto Police Service via AP)

But at the same time, investigators are conducting a comprehensive digital forensics investigation to track McArthur’s apparent methods of picking his alleged victims.

There are also international agencies involved in seeing how far McArthur’s alleged activities may have extended, authorities added.

“It’s getting bigger,” said Hank Idsinga, a homicide detective sergeant with the Toronto Police, “and we are getting more resources.”

The first two victims whose deaths McArthur was charged with were Andrew Kinsman, 49, and Selim Esen, 44. Both were last seen in the “Gay Village” section of Toronto. Kinsman went missing last June, and Essen last April. The search for them was part of a Toronto task force called “Project Prism,” authorities have said. (Parts of Kinsman were found recently at the suspect property.)

But just over a week later, McArthur was charged in the deaths of three more men: 58-year-old Majeed Kayhan, who was reported missing in 2012; Soroush Mahmudi, 50, reported missing in 2015; and Dean Lisowick, a 47-year-old man reportedly homeless who vanished sometime between 2016 and 2017. (Lisowick was never reported missing.)

The police have checked 30 overall sites where McArthur did landscaping. Along the way, they have seized 15 planters, which are still being processed.

“Police continue to search properties associated with Mr. McArthur and are asking anyone who received landscaping services from him to contact police, if you have not been contacted already,” police said on Jan. 29.

“I have no idea how many more there are going to be,” said Idsinga, at the Jan. 29 presser.

The digital forensics aspects of the case reportedly focus around McArthur’s activities on gay dating apps such as “Manjam,” “SilverDaddies” and “Bear411.”

McArthur reportedly had an active Facebook account showing nightlife and vacation trips, but it has since been removed.

The Associated Press contributed to this report.