The newly released documents indicate the RCMP want to dig deeper into the former Conservative's financial affairs.
Brazeau has been accused of breach of trust by filing allegedly inappropriate travel and housing claims, and the lead Mountie in the case has asked the Senate for more information, including attendance records.
Brazeau's passport and Quebec driver's licence at one time listed his former father-in-law's house on the Kiniw Zibi Mika First Nation reserve at Maniwaki, Que., as his address.
A court document, filed Thursday by RCMP Cpl. Greg Horton, said Brazeau did not live there but used the address to claim aboriginal income-tax exemptions between 2004 and 2008. A "further investigation pertaining to those income tax claims" and the use of Daryl Tenasco's address would be conducted, Horton states.
That criminal probe is apart from the breach-of-trust Senate allowance investigation, and from charges of assault and sexual assault filed in February in relation to a case that involved a disturbance at his house in Gatineau.
Brazeau, 38, has pleaded not guilty to the assault charges, and both sets of expense allegations have not been proven in court.
Through interviews and statements in the Senate expense probe, RCMP say Brazeau claimed to be living at his father's house in Maniwaki, about 140 kilometres north of Ottawa.
"The investigation has shown Brazeau does not live in Maniwaki, nor does he own a home there," said the court filing, known as a production order.
Senators who live more than 100 kilometres outside the capital are allowed to claim housing costs for a second residence in Ottawa, an allowance that has been under growing scrutiny.
The RCMP is also investigating former Conservative Sen. Mike Duffy and Liberal Sen. Mac Harb for breach of trust.
Brazeau, a former high-profile aboriginal leader, was appointed to the Senate in December 2008. At the time, the Privy Council Office, the bureaucratic wing of Prime Minister Stephen Harper's office, asked the RCMP to conduct a background check, and the address listed was a home in Gatineau, just across the river from Ottawa.
The investigation, which touches on the senator's turbulent personal life, showed that Brazeau did not start filing for the Senate housing allowance until three months after he and his wife separated in December 2010, say the court documents.
He switched his primary residence listing from the family home in Gatineau to his father's home at Maniwaki, making him eligible for tens of thousands of dollars in housing and mileage expenses.
An independent audit of Brazeau's expenses resulted in a Senate committee ordering him to repay $48,000. The Senate has started docking his pay in order to collect.
Police interviewed his ex-wife, former father-in-law, assistants and neighbours, including the music teacher living above his father's home, who said Brazeau hasn't lived there in 16 years and "cannot recall ever seeing him" at the residence.
Lorraine Rochon, the senator's executive assistant, told police Brazeau "visited Maniwaki once or twice a month," and inquired with the Senate finance wing about his eligibility for the housing allowance.
Defending himself publicly, Brazeau has said an email response from Senate employee Nicole Proulx was proof the upper chamber gave him the green light for expenses, but Horton's sworn statement says the email was not definitive.
"I do not interpret Ms. Proulx's response as authorization for Senator Brazeau to commence claiming a (national capital region) housing allowance, but rather direction on where Ms. Rochon can read the policy pertaining to such matters."
A neighbour who lived close to the home Brazeau claimed as his second residence in Gatineau say they assumed he lived there full-time.
Denise Fontaine, whose Gatineau home faces Brazeau's backyard, said she did not know the senator very well, but saw him from time to time.
"I do not know this gentleman," she told The Canadian Press in French during a telephone interview.
"He lives, as I said in the documents of the RCMP, he was renting a house on our little street, which is a private street in Gatineau, and then he was often in the way, but I cannot say more to you."
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