Police display $477,050 US they say was found hidden in a horse trailer. (Harnarayan Singh/CBC)

Police are looking for an Ontario man accused of trying to smuggle more than $477,000 US into Alberta from Montana in a horse trailer.

Joseph Dale Butler, 34, of St. Thomas, Ont., has been charged with possession of the proceeds of crime over $5,000 and laundering the proceeds of crime, the RCMP said Thursday. A warrant has been issued for his arrest.

Police said Butler is also the first person charged with failure to report importation of currency into Canada under the Proceeds of Crime and Terrorist Financing Act.

On April 20, border officials in Coutts, Alta., seized $477,050 US found in a gym bag hidden in a false compartment between a trailer's livestock area and the living quarters. RCMP also seized a 2005 pickup truck and the horse trailer.

"This is the largest seizure in Alberta, in the Prairie region, to date," said Candace Lyle of the Canada Border Services Agency.

Butler was then arrested but released without charges. At the time, police said the man arrested at the border was from Calgary.

Money may be from drug trade

An investigation, which included help from U.S. officials, revealed the seized money was associated with crime, most likely the cross-border drug trade, RCMP Staff Sgt. Stephen Scott.

"By laying a charge, we give this person a criminal record and ... he's probably a highly trusted member of that organization. If he gets convicted and gets a record, he's no longer necessarily able to cross international borders so he's useless to that organization," said Scott.

Butler was charged on Sept. 23.

There are no restrictions on the amount of money that can be taken into or out of Canada, but any currency totalling more than $10,000 must be reported at the border.

The Coutts border crossing, about 300 kilometres south of Calgary, is one of the busiest in Western Canada.