A truck belonging to a former military reservist linked to a global neo-Nazi group has been found in southern Manitoba near the U.S.-Canada border, but there was otherwise no sign of Patrik Mathews, according to the RCMP.

Mathews has been missing for more than a week and the RCMP confirmed Tuesday his red Dodge pickup was found Monday on a rural property in Sprague, Man., off Highway 12 near Road 81E, about 145 kilometres southeast of Winnipeg.

The vehicle is believed to have been parked there for roughly a week, police said in a news release.

"Officers attended the location and confirmed the vehicle as belonging to Patrik Mathews. A search of the immediate area did not locate him," the release states.

Police are urging the public to avoid engaging with Mathews if they see him, and to contact police immediately.

"The RCMP believe Mr. Mathews may be under a significant amount of pressure due to this ongoing investigation and the extensive media coverage it has garnered," the release says.

There are no indications Mathews has crossed into the U.S., an RCMP spokesperson later told CBC News.

Sgt. Paul Manaigre said via email other law enforcement agencies, including the Canada Border Services Agency, have been notified.

In an email, a spokesperson for U.S. Customs and Border Protection said it was contacted by RCMP and is ready to assist, if needed.

Manaigre also said there's no indication Mathews knew the owner of the property where his vehicle was found.

Mounties swarmed Mathews' home in Beausejour, Man., on Aug. 19 and seized a number of firearms after a Winnipeg Free Press investigation into the Base, a neo-Nazi group trying to establish itself in Manitoba. Mathews was neither arrested nor charged with any crime.

A spokesperson confirmed Aug. 25 that the eight-year member of the reserves had been released from the Canadian Armed Forces. The next day, the RCMP said he had gone missing.

He is being investigated by the RCMP and the Forces for alleged ties to the Base, described by anti-hate activists as a white supremacist group that tries to get its members into the military to train for what it says is a coming race war.

Mathews worked as a combat engineer and had basic explosives training as a member of the Winnipeg-based 38 Canadian Brigade Group. The former master corporal had also received leadership training and was in charge of a group of reserve soldiers.

Posters for the Base appeared on the streets in Winnipeg this summer, and Mathews is alleged to have been involved in trying to recruit new members.

Mathews went missing shortly after his alleged links to a neo-Nazi group were reported by the Winnipeg Free Press. (Courtney Rutherford/CBC)

There were conflicting initial accounts from the Forces over when they first became aware of Mathews' alleged link to the Base.

His brigade commander told the media the military had no knowledge of the alleged link in May, when Mathews worked his last shift with the reserves. Days later, Chief of Defence Staff Gen. Jonathan Vance said the military's counter-intelligence unit became aware of it in April.

The military has refused to provide details of its investigation.

Anyone with information of his whereabouts is asked to contact RCMP at 204-268-1234 or Crime Stoppers anonymously at 1-800-222-8477. Tips can also be submitted confidentially online.

Anti-hate advocate 'stunned'

Bernie Farber, chair of the Canadian Anti-Hate Network, said he's "stunned" Mathews has been able to elude police.

"Had Mr. Mathews instead been an ISIS agent … I just don't think we would be having a conversation like this," Farber said in a phone interview on Tuesday.

Farber said he wants to see the military train members to recognize and address hate organizations in their ranks, and wants urban police services to reinstate hate crime units he says were more common in the 1990s and early 2000s.

Posters for the Base have been put up in various locations around Winnipeg since late July. Mathews is alleged to have recruited for the group. (Facebook/FF1)

"I think that there should be kind of a reckoning … the RCMP have to be a little bit more transparent. The military has to be a little bit more transparent," Farber said. "This whole thing is turning into a bit of a fiasco."

Alain Hogue, a lawyer in Winnipeg, said he thinks Canada should strengthen laws that deal with extremism and white supremacy.

"It's an issue that will continue to grow, because the right is getting stronger, we know, across the West," Hogue said. "We thought Canada was immune, but we're not immune."