The RCMP and Canada Border Services Agency back in September investigated and even briefly detained a Canadian woman now under arrest in Mexico, CBC News has learned.

But Canadian officials are saying little about why, as Mexican authorities hold Cyndy Vanier of Mount Forest, Ont., without charge, alleging she is the leader in an international plot to shelter and hide al-Saddi Gadhafi, son of former Libyan dictator Mommar Gadhafi.

"We are aware of her arrest in Mexico," wrote RCMP Sgt. Richard Rollings in an email to CBC News. "While the RCMP does not share details of ongoing investigations, we are working with domestic and international partners to establish if any criminal offence was committed in Canada."

Vanier flatly denies any wrong-doing.

"She had nothing to do with anything to do with Saadi Gadhafi, or getting him out of Libya, or getting him to Mexico, or any human smuggling operation," said her Toronto lawyer, Paul Copeland, in an interview with CBC News.

"I am interested in getting some answers to what the Canadian authorities role was in all of this," said Copeland, explaining Mexican officials have now also seized her family's vacation condominium which she was visiting at the time of her arrest.

Copeland says Vanier learned she was on RCMP radar in early September when an officer came to her home in Mount Forest, where she runs Vanier Consulting, a company specializing in "high-risk, unconventional mediation work."

The visit was timely. Libya was increasingly falling under rebel control and Gadhafi family members were trying to flee the country, under growing UN sanctions restricting their travel and freezing the dictatorship's assets.

Vanier had been in Libya in July on a fact-finding mission for Canadian engineering giant SNC-Lavalin.

She hired private Canadian security contractor Gary Peters to protect her and to arrange travel on her 10-day visit.

But Peters reportedly had other clients in Libya, including members of the Gadhafi family. A recent series of stories in the National Post cites the CEO of a Canadian-based security firm saying he was hired to escort a number of Gadhafi family members out of the country, including arranging a heavily armed convoy around Sept. 11, to escort al-Saadi Gadhafi and his family to nearby Niger. Further in the Post report, Peters insists it was all legal.

Just days later, back in Ontario, RCMP officer Angelo Capra with the Integrated National Security Enforcement Team, showed up on Vanier's doorstep, asking questions.

"There was a travel ban against Saadi Gadhafi, and there was some suggestion [from the RCMP officer] she had some involvement in violation of that," says Copeland, adding his client spoke at length to Capra.

On Sept. 14, the RCMP officer returned to ask more questions, according to Copeland, at which point she asked to have her lawyer present. Copeland wrote numerous letters and emails to the RCMP (which he supplied to CBC News) asking for more information and offering to set up an interview within days. Copeland says the RCMP never called back.

Interpol only issued a "Red Notice" international warrant for the arrest of al-Saadi Gadhafi on Sept. 29, weeks after he'd fled Libya.

CBSA detained Vanier, searched planes

On Sept. 25, Vanier was stopped at the Kitchener-Waterloo airport by Canada Border Services Agency officials upon landing aboard a privately chartered airplane returning from Mexico. According to letters Copeland sent to CBSA, officials demanded to see her travel documents and asked to photocopy them.

"She arrives on a private chartered flight and gets extensively searched by CBSA people ... and the plane was extensively searched," says Copeland.

He told CBC News the privately chartered airplane was paid for by a client, but he said he was unaware of the details.

On Oct. 20, Vanier was delayed again, this time trying to board a charter flight departing from Kitchener. According to a letter of complaint Copeland sent days later to CBSA president Luc Portelance: "The search included sniffer dogs. When the first round of the search found nothing, the CBSA supervisor told the staff to search the plane again. It appeared to my client that they were trying to stall my client's departure."

CBSA wrote back insisting, "CBSA actions on the evening of Sept. 25 were entirely within their mandate and did not include any RCMP involvement."

Lawyer questions role of private security contractor

Copeland says he can’t understand why Mexican authorities have arrested Vanier – when it appears Peters has more information about the alleged plot involving al-Saadi Gadhafi and his family.

"From what I've seen from the National Post stories, and what Mr. Peters claims that he was involved in, I don't understand why he's not in custody!" said Copeland.

The National Post has run numerous articles, reporting Peters has stated he had worked for various Gadhafi family members, was aware of the plot to move al-Saadi Gadhafi to Mexico, including having twice visited a luxury home in Punta Mita where Mexican officials allege Gadhafi and his family planned to live under false identities. Peters, according to the Post, has insisted he always understood the relocation plan was legal, sanctioned by the Mexican government, and did not involve any crimes.

"Well he's fully admitted his involvement in smuggling Saadi Gadhafi out of Libya into Niger. He's fully admitted involvement in a plot to get him to Mexico. Seems to me if what they are alleging against my client is an offence, what he has admitted to constitutes an offence, or several offences," says Copeland.

Copeland is relying only on what was reported in the Post. CBC News has repeatedly telephoned and emailed Peters but he has not responded to requests to verify the National Post reports.

Copeland says Vanier broke off ties with Peters months ago, unhappy with his work in Libya. He says Vanier has hired lawyers in Mexico — but that they are having difficulty getting specific details from Mexican authorities about the accusations against her.

Under Mexico's 'preventative arrest laws,' Copeland says authorities can continue to hold her for 40 days without charge, which expires Dec. 22.

Tips on this story? Please send to Dave.Seglins@cbc.ca.