They're supposed to be the buffer between government and any appearance of conflict of interest.

But when the special prosecutor who cleared British Columbia's solicitor general of election wrongdoing stepped down this week, he did just the opposite.

Terrance Robertson resigned and revealed that his law firm had donated to Heed's campaign.

Yet the names of at least 15 of the 35 lawyers on the list of potential special prosecutors or their firms are also on Liberal party donation lists.

This includes lawyers involved in some of the province's most high-profile cases, including the legislature raid case and a lawyer who has been appointed to argue against Canada's polygamy laws.

Bill Berardino, the special prosecutor in the lengthy legislature raid case, is listed as "principal officer" for two donations in 2005 by his law firm at the time, Berardino and Harris LLP. The firm gave $500 to former attorney general Wally Oppal and $100 to the Liberal party.

Berardino, who said the contribution to Oppal was made at a fundraising breakfast, had already been special prosecutor for more than a year when the donations were made.

In light of the recent developments just as the raid trial is about to start, he said he asked a prominent former judge for an opinion on the matter.

"I thought I should ask someone else to tell me what I already know, which is there is no conflict," he said of retired B.C. Supreme Court justice Thomas Berger.

"He has told me that I have no conflict of interest, and more over, I have a public duty to carry on the prosecution."

George K. MacIntosh was nominated by the province and appointed by a B.C. Supreme Court judge as amicus in a forthcoming court reference case on Canada's polygamy law. MacIntosh will argue opposite the attorney general, against the federal law barring polygamy.

Elections B.C. lists a George K. MacIntosh as having personally donated $2,500 to the Liberal party in 2005. MacIntosh couldn't immediately be reached for comment.

His firm, Farris, Vaughan, Wills and Murphy, has given more than $50,000 to the Liberals since 2005.

In the solicitor general's case, Robertson publicly disclosed his firm's donation after clearing Heed of wrongdoing in his election campaign investigation. It has since been revealed Robertson also made a personal contribution of $1,000 to the Liberal party last year.

And there are others.

Richard Peck was special prosecutor reviewing the possibility of polygamy charges in the community of Bountiful three years ago. His law firm donated $1,000 to the Liberals in 2005.

Another on the list is Kris Pechet, who was assigned last year to the prosecution of a woman accused of criminally harassing the attorney general, donated $500 to a Liberal candidate.

The revelations give at least the appearance of conflict of interest and fuel distrust among the public, legal observers say.

"I hope you don't need a specialist in legal ethics to tell you that's a problem," Lorne Sossin of the University of Toronto said in an interview.

"The issue isn't, 'Are these people really motivated by some affinity for the government as reflected in having made a donation?' It really is a perception-based concern, and perception is everything."

Sossin said it's probably not necessary to publicly disclose every potential conflict, and lawyers who've donated in the past shouldn't be automatically barred from such a position.

But he said there must be safeguards in place to ensure potential conflicts are identified and reviewed before an assignment is made. And, in some cases, make a point to tell the public.

"The more that's transparent and the more we put in the public realm, the higher the bar is for the public realm to justify that these appointments are truly merit-based," said Sossin, who is also director of the Centre for the Legal Profession.

Special prosecutors are appointed from a list of senior lawyers in private practice who have been jointly approved by the president of the B.C. Law Society, the deputy attorney general and the assistant deputy attorney general, according to attorney general ministry's website.

Only the head of the province's prosecution service, the assistant deputy attorney general of the Criminal Justice Branch, has the authority to appoint one.

Law professor Penny Collenette of the University of Ottawa said law firms routinely give money to the political process, and that shouldn't be discouraged.

She said the personal donations are more troubling, especially when Robertson's weren't revealed until after he'd made a decision.

"Most law firms will donate somewhere along the lines for a political party, that's a fact of life," said Collenette, who ran for the federal Liberals in 2008.

"The personal one, that's a little more troubling. Can you say anything's wrong? No. Is the appearance a little grey? Yes. It's the perception and the optics."

The Robertson case has prompted an investigation by the law society, and Attorney General, Mike de Jong, said he'll conduct his own review.

"It (the special prosecutor system) has generally worked reasonably well; it did not work here," said de Jong.

"We're looking at why that was so, how that was allowed to happen, and what changes can be made to prevent it from happening again."

Stephen Owen, a former provincial ombudsman and former deputy attorney general who was involved in setting up B.C.'s special prosecutor system in the early 1990s, said the controversy highlights the need for more vigilant vetting.

He doesn't think it should prompt any major policy changes.

In the Heed case, Owen said the province should appoint a new special prosecutor to start the process from the beginning, rather than simply picking up where Robertson left off.

"They need to appoint another special prosecutor . . . to redo the whole investigation to see if charges should be laid, including against Mr. Heed," said Owen, who now works for the University of British Columbia.

"The public should have full confidence that there are no such conflicts. And it's only fair to Mr. Heed, because there will be a cloud over the fact that he wasn't charged."