The leaders of Nova Scotia's three main parties say public trust in the province's politics has been more deeply shaken after the RCMP laid 52 charges on Monday against one current and three former members of the legislature.

The charges, resulting from a criminal investigation of members' constituency expenses, include fraud, theft and breach of trust.

Premier Darrell Dexter said the charges will make it more difficult to get people to participate in politics.

"You know frankly, I'm not just disappointed, I'm angry about it because we all have to live with the consequences," he said.

Dexter refused to comment on the individual cases but he said the fallout from them will make it difficult for all political parties.

"It just becomes much more difficult to bring people into public life," he added.

At the end of a nine-month investigation, RCMP said all four men have been charged with fraud exceeding $5,000 and breach of trust by a public officer.

All of those charged are scheduled to make their first appearance in Halifax provincial court on April 20. None of the allegations against the men have been proven in court.

Among those charged are two former cabinet ministers, Conservative Richard Hurlburt and former Liberal Russell MacKinnon.

Dave Wilson, a former Liberal member of the house, is also facing 31 counts of uttering a forged document. Hurlburt faces three counts and MacKinnon eight counts of uttering a forged document.

Trevor Zinck, an Independent member of the house who was elected as a New Democrat, has also been charged with two counts of theft over $5,000.

Insp. Jim MacDougall of the RCMPs commercial crime section said two other politicians were investigated but not charged.

He said officers "pored over thousands of documents and spent countless hours reviewing information" gathered during their investigation.

At a news conference, MacDougall would not discuss any of the specific allegations against the four men.

He also said the investigation is closed and police have no plans to investigate constituency expenses beyond a three-year period examined by the auditor general.

"The RCMP investigates only what complaint is made to them, so we investigated the allegations that were before us," said MacDougall.

Auditor general Jacques Lapointe released a report just over a year ago that uncovered several cases of what he described as excessive and inappropriate spending of constituency funds allotted to the 52 members of the legislature.

The RCMP began its criminal investigation after Lapointe handed forensic audit files to the Mounties last May on specific transactions involving five former members and one current member. It's not known what allegations were made in Lapointe's forensic audit.

Liberal Leader Stephen McNeil said he was angry as well over the outcome of the police investigation.

"This feeds right into the cynicism that's out there in the public that people who are elected to the House of Assembly are crooks and are in it for their own good," said McNeil. "I don't believe that, but this doesn't help."

Conservative Leader Jamie Baillie said members of the legislature need to rebuild trust in the province's political system.

"Today's charges are the result of a system where MLAs could set their own rules," he said in a statement.

Changes were put in place to make the expense system more open to public scrutiny.

Legislature Speaker Gordie Gosse said a person can remain a member of the legislature while court proceedings take place but a conviction would result in a member being removed from the house.

Generally, Lapointe's original report released last February alleged that politicians had spent thousands of dollars on everything from home installed generators and big-screen TVs to custom-made furniture and espresso makers. He looked at spending by members of the legislature between July 2006 and June 2009.

Lapointe's report didn't name politicians but after it was released members of the house came forward and explained how they had spent their constituency allowances.

Hurlburt said he spent $8,000 on a generator that was installed at his home. It was installed, he said, for the use of a nearby seniors home. He later resigned and repaid the money to the province.

Hurlburt's lawyer, Martin Pink, had no comment on the charges.

Wilson said he repaid $400 that was spent on patio furniture.

Wilson was also in the news at the time after the NDP, Liberals and Conservatives released figures showing how much their members spent on extra staff and extra pay for their constituency assistants.

Of those who submitted documentation in the Liberal party, Wilson spent the most, confirming that he paid his constituency assistant more than $24,000 on top on their regular salary over an 18-month period. He also paid more than $37,000 over the course of three years to other staff.

He later resigned from the legislature without explanation.

The former broadcast journalist in Cape Breton and Saint John, N.B., was first elected to the legislature in 1999 and was re-elected five times.

Former legislature Speaker Charlie Parker has said Lapointe looked into Zinck's spending after June 2009, as well as during the original audit period.

In March, Zinck acknowledged he was late in paying constituency office bills for electricity, telephone and Internet because of a turnover in his office staff and because he had to assist in the care of his ailing father. He has said his constituency office bills were paid.

Zinck represents the riding of Dartmouth North and was elected as a New Democrat before he was kicked out of the party's caucus over the bills.

In a statement, Zinck said the charges against him have not been proven in court and he would make no comment on them.

MacKinnon, who represented Cape Breton West until 2006 when he lost a nomination race after switching to the Tories, said he looks forward to his day in court.

"I am glad that charges have finally been laid and that I will have my day in court and finally end months of speculation and innuendo," MacKinnon said.