The RCMP laid 31 charges of fraud, breach of trust and bribery against suspended Sen. Mike Duffy on Thursday.
The charges involve Duffy's claims for living expenses, claims for travel expenses unconnected with Senate business and fraudulent contracts, said RCMP Assistant Commissioner Gilles Michaud.
They also cover the $90,000 Duffy allegedly received from Nigel Wright, the prime minister's former chief of staff.
A spokesman for Prime Minister Stephen Harper called the behaviour described in the RCMP charges "disgraceful."
"We have assisted the RCMP throughout their investigation, and congratulate them on the progress they have made," Jason Macdonald said in a statement.
"Those who break the rules must suffer the consequences. The conduct described in the numerous charges against Mr. Duffy is disgraceful."
"As this is now a criminal matter that is before the courts, we have nothing further to add."
The opposition, meanwhile, blamed the charges on Harper, who appointed Duffy to the Senate.
"These charges and the scandal stem from the poor judgment of the prime minister," said New Democrat MP Nycole Turmel. "The buck stops with Stephen Harper.
Liberal MP Marc Garneau echoed that.
"These charges are extremely serious," Garneau said. "Mike Duffy is a legislator in Canada's Parliament and the prime minister of this country is the one who put him there."
"Throughout this entire PMO ethics scandal, the prime minister has tried to evade responsibility."
Michaud said the charges cover more than $200,000 in phoney expenses.
They include money Duffy claimed for living expenses in what he said was a secondary residence in Ottawa, as well as expenses he charged for travel on personal or political business.
The bribery charge covers the $90,000 payment from Wright.
"The investigation into Sen. Mike Duffy has been completed," Michaud said at a news conference.
"The case was initiated as an investigation into expense claims relating to his declared primary residence in Prince Edward Island, and secondary residence in Ottawa."
Michaud said the investigation then widened into four different directions.
The first involved expense claims relating to Duffy's secondary residence in Ottawa, while the second covered the filing of Senate expense claims for travel for personal and partisan reasons, unrelated to Senate business.
A third avenue covered the awards of consulting contracts over a four-year period and the use of part of those funds for personal gain or for expenses that circumvent Senate oversight.
The last involved the $90,000 Duffy got from Wright to repay his residency expense claims.
Duffy's first court appearance is set for Sept. 16.
The charges could result in a prison sentence. The bribery count carries a maximum sentence of 14 years.