Toronto police said an investigation Monday at the Waterloo Region farm of Dellen Millard was related to the disappearance of Laura Babcock.
The 23-year-old Toronto woman, who police said had a relationship with Millard, was reported missing in June 2012.
A Toronto police forensic vehicle and several detectives in plainclothes were seen at the North Dumfries Township property. Investigators could be been seen entering and exiting the farm's barn.
Later Monday, officers from Waterloo Regional Police's drug unit were at the scene and searched the barn. Both forces had wrapped up their search around 6 p.m., with only a single Waterloo cruiser remaining to guard the property.
A search warrant was executed at the farm Monday morning, Toronto police said.
Police declined to provide any more details, other than to say that new information led to the latest search.
Babcock's cellphone records show Millard was one of the last people she called before she went missing.
Laura Babcock's mother, Linda Babcock, told CBC reporter Marivel Taruc in a brief interview on Monday that she will stay positive.
"I'm being totally optimistic," she said.
Burned human remains were previously located on the farm, and investigators said they were confident they belong to Hamilton man Tim Bosma.
Earlier, police found an incinerator on the farm that they say Millard purchased last July. The machine, known as The Eliminator, is used to cremate livestock, but police said Millard didn't own any animals.
Millard, the 28-year-old heir of a family aviation business, was charged with kidnapping and killing Bosma after the husband and father disappeared after he went on a test drive of a truck on May 6 with two strangers who responded to an online ad.
Police have also charged Mark Smich, 25, with first-degree murder in Bosma's death.
Millard's lawyer, Deepak Paradkar, said his client has not been interviewed recently about Babcock and he didn't know about the search warrant being executed. Millard's next court appearance is set for Thursday.