Allegations against a former senior advisor to the prime minister show serious ethical lapses with the government, Liberal Leader Michael Ignatieff said Thursday.

Ignatieff's comments came ahead of new allegations about Bruce Carson's alleged dealings with a water purification firm that hoped to get contracts with First Nations communities and the government.

Carson is a former top adviser to Prime Minister Stephen Harper. On Wednesday, the Prime Minister's office announced he'd referred allegations about Carson to the RCMP. Carson faces accusations he told H20 Pros, a water purification company, he could use his connections to arrange deals between the company and First Nations communities.

A report Thursday by the Aboriginal People Television Network suggested Carson's fiancée, Michele McPherson, acted as an intermediary between H20 Pros and the First Nations communities, and stood to earn commission from any sales. It also said she has worked as an escort.

The APTN investigation also alleged he lobbied officials at the Department of Indian and Northern Affairs Canada. It's illegal for former senior staffers to lobby for five years after they leave their jobs. Carson left two years ago and told APTN he is not registered as a lobbyist.

"This is a very, very serious allegation of influence peddling," Ignatieff said.

"This is a man who was in the inner circle of Mr. Harper's team, who's been accused of seeking financial gain for a company," Ignatieff said, adding it's the second case this week the Conservative government has asked the RCMP to investigate.

"It suggests to you that there's some serious ethical lapses or lapses of judgment on the part of this government," Ignatieff said in Welland, Ont.

Public Works and Government Services Minister Rona Ambrose also asked the police force to look into a report from the Information Commissioner that found Sebastien Togneri, a former Tory staffer, interfered with an Access to Information request.

A spokeswoman for the RCMP says the force is evaluating the information about Carson provided by the Prime Minister's Office and haven't decided whether to investigate.

Carson, who became executive director of the University of Calgary's Canada School of Energy and Environment, issued a statement Wednesday night saying he is taking a leave of absence until the RCMP probe is completed.

Known Carson for years: Atleo

Shawn Atleo, Chief of the Assembly of First Nations, and a former colleague of Carson's, told CBC's Power & Politics he's known Carson for years.

Atleo said he meets with hundreds of companies who say they have solutions to First Nations water-quality problems, but tells them to speak directly the communities.

"It's up to those companies to have direct conversations with First Nations," he said.

A statement released later by the AFN says they don't "endorse, promote or support any product, service or company with which Mr. Carson is or was involved."

It goes on to say the AFN became aware last October Carson and his representatives "were making claims to that effect and we moved immediately to make him and his colleagues stop."

In his own statement Wednesday, Carson explained why he is stepping aside from his Calgary position.

"Out of respect for this process, the Office of the Prime Minister, and the many business and community leaders with whom I work, I will be taking a leave of absence effective immediately from all of my professional responsibilities until the investigation is concluded," he said.

Carson said he could not make any further comments, and indicated he had retained a lawyer.

CBC News was unable to reach him.

Indian Affairs

APTN says on its website it has a copy of an email Carson sent to H20 Pros in which he claimed advance knowledge about John Duncan's appointment as Indian affairs minister.

"I spoke with the PM last night and with  Atleo — the movement of John Duncan to INAC does not slow anything down," APTN reports Carson wrote in an email.

"Both Shawn and I know John very well — and I will be calling the new Minister this morning — so it is still full steam ahead."

Carson denied that claim in a videotaped interview with APTN.

Asked whether he still spoke to Harper, Carson said, "We talk on a regular basis, I talk to a number of his ministers on a regular basis."

A spokesman for Harper said in a statement Wednesday night that the prime minister has never met with, spoken with or been lobbied by Carson on "these matters," though he didn't specify what those matters are.

"The laws are clear and they must be respected. Those who do not respect them must and should face the full force of the law as well as the consequences that come with it," Dimitri Soudas wrote in an email.

"Given what we've learned about Bruce Carson, our government will not be in communication with him on any matter," he added.

A spokeswoman for Duncan said Thursday someone from their office met with Carson on Jan. 11, 2011, although it's not declared on the federal lobbyist registry. It's up to the lobbyist to declare meetings with public office holders.

"The minister has never met with, been spoken to or been lobbied by Bruce Carson on these matters," Michele-Jamali Paquette wrote in an email.

"The minister's staff met with Bruce Carson on one occasion. Mr. Carson briefed the staff on the proposed water project. Staff provided publicly available information to Bruce Carson and recommended he work directly with First Nations."

Conservative MP Ted Menzies addressed the controversy briefly after a committee appearance in Ottawa Thursday morning.

"I'm a proud Canadian and a proud believer in the fact that people are innocent before proven guilty. That's all I know," Menzies said.

Meanwhile, NDP energy critic Pat Martin criticized the PMO for waiting so long to investigate Carson.

"The PMO is trying to get out in front of a scandal the likes of which we haven't seen in a long, long time," said Martin. "Throwing Carson under the bus is going to be too little too late."

With files from Canadian Press