LEWISTON — A prominent Portland law firm’s top tier of attorneys on Wednesday told a judge, one by one, that they had no reason to believe one of the firm’s veteran lawyers who’d been stealing from the firm would lie about the scope and nature of his activities.

“John Duncan was somebody within the firm that everybody respected and had a lot of credibility,” said James Kilbreth III, who was chairman of Verrill Dana’s executive board in 2007.

They later would learn that Duncan had embezzled nearly $300,000 from six of the firm’s clients as well as the firm itself.

Duncan was convicted in 2008 on two counts of theft and sentenced to two years in federal prison.

But it wasn’t Duncan who was on the hot seat this week in 8th District Court where Maine Supreme Judicial Court Justice Donald Alexander presided over a three-day hearing.

Kilbreth and four other board members, along with the firm’s then-managing partner, are accused by the Maine Board of Overseers of the Bar of several ethics violations under Maine Bar Rules.

J. Scott Davis, bar counsel and prosecutor, wrote in his charging document that the six lawyers not only turned a blind eye to the illicit activities of one of their own, but they received stolen property from him.

Duncan was suspected of stealing by his secretary, who collected evidence of his wrongdoing and took it to another lawyer in the firm early in June 2007. That lawyer passed the file of evidence along to David Warren, the firm’s managing partner at the time. Warren shared the secretary’s suspicions with Kilbreth.

Believing Duncan had bilked the firm out of $77,500, they confronted Duncan, who confessed and promised to repay the money. He also offered to resign from the firm.

The lawyer, who’d been at the firm for 30 years, was described by the defendants as emotionally and physically fragile. He sobbed when approached about the matter.

Warren also had learned the married Duncan had been carrying on a gay affair and was surfing pornography on the company’s Internet and was sending and receiving sexually explicit e-mails with his lover.

Duncan had a bleeding ulcer and his father was ill. Warren testified Monday that he feared Warren might kill himself, having worked at another firm where a fellow lawyer had done just that. Others at the firm shared his concern.

Members of the executive board said Wednesday that Warren informed them of Duncan’s activities at a July 9 meeting. Warren said Duncan had readily admitted his guilt and had written a check for the stolen $77,500. Warren had assured the board that Duncan had not stolen any money from the firm’s clients because he asked Duncan, who looked him in the eye when he answered that he hadn’t.

That would turn out to be one of several lies Duncan told Warren and others who quizzed him about his illicit activities.

At the July 7 meeting, members of the executive board agreed that the head of Duncan’s department at the firm, which deals with estates and trusts, should be told about Duncan’s affairs.

But, as Davis pointed out repeatedly during the three-day hearing, Warren didn’t tell the departmental head, Kurt Klebe, until Oct. 2, about four months after the matter came to light. Warren invited Klebe to lunch and told him about the $77,500 and the misuse of the firm’s computers. Klebe shared his information with another of the firm’s lawyers.

Things started happening quickly.

A paralegal had discovered a discrepancy of $5,000 in another client’s account that was linked to Duncan. She told Klebe. He began investigating Duncan’s other accounts and found further instances of improper transactions, involving other clients.

Klebe’s colleague had noticed Duncan had been billing more than normal for the client whose account had the $5,000 discrepancy.

Before the end of the month, the firm had asked for Duncan’s resignation and soon notified authorities and the Maine Board of Overseers of the Bar about his improper check writing. The firm also engaged the services of auditors to unravel Duncan’s ball of misdeeds.

Members of the executive board said Wednesday they had encouraged Warren to contact Klebe about Duncan’s activities as soon as they learned about them. But Warren had told them he was worried about further upsetting the unstable partner and wanted to wait. He also recommended to the board that the firm not accept Duncan’s resignation. They unanimously agreed.

None of the four board members had learned details about any of Duncan’s other activities until later in October, they said.

Their attorney, Peter Rubin, motioned Wednesday to have the judge drop several of the charges against them, arguing they hadn’t been privy to information that would suggest Duncan had stolen directly from clients and had padded his bills to clients, all things Duncan’s secretary had shared with one of the firm’s lawyers on June 5.

Gene Libby, the firm’s general counsel, said Wednesday he expected to be notified of any ethics issues at Verrill Dana. But he didn’t learn there was any “Duncan matter” until he received a fax on Oct. 10 from Daniel Lilley, an attorney for Duncan’s secretary who had left the firm after handing over her Duncan file in June.

The defendants in the case called as an expert witness Auburn lawyer Bryan Dench, who is the “go-to” attorney on ethics issues for Skelton, Taintor and Abbott. Dench also represents the Androscoggin County Commission and the Sun Journal newspaper.

Given the limited information known to members of Verrill Dana’s executive board in July 2007, Dench said he believed it was reasonable for them not to have reported Duncan’s actions to the Maine Board of Overseers of the Bar.

Both the prosecution and defense rested their cases Wednesday. They are scheduled to appear in Maine Supreme Judicial Court on Friday for closing arguments.