A federal appellate panel seemed skeptical of Boston criminal defense attorney Robert George’s argument that his money laundering conviction should be overturned because the judge erroneously allowed certain evidence.

On Monday, the U.S. Court of Appeals for the First Circuit heard debate in United States v. George. Boston federal judge Nathaniel Gorton sentenced George to 3 1/2 years in prison in October 2012 on five counts of money laundering, one money laundering conspiracy charge and one charge of structuring, or parceling out large transactions into smaller ones.

In 2011, the government charged George and a co-conspirator with hiding more than $225,000 in drug proceeds. The co-conspirator was later identified as mortgage broker Michael Hansen.

George’s brief argued that Gordon should not have admitted “highly inflammatory and unduly prejudicial conversations” between Hansen and Ronald Dardinski, a former George client and government informant.

He argued that the government lacked enough evidence to make its case. The evidence, the brief said, showed that in April 2009, George withdrew from any arguable conspiracy. The government’s case pegged the conspiracy period from February 2009 to June 2010.

Judges William Kayatta Jr. and O. Rogeriee Thompson sat on the panel with Senior Judge Norman Stahl.

To make its case, the government literally threw cash at George at a time when he was financially strapped, according to his lawyer, Robert Goldstein of Boston’s Goldstein Law Firm. Hansen gave George $20,000 in cash in fall 2010, according to the brief.

“Simply because he accepts that money outside the period of the conspiracy does not … undermine the pre-existing verbal and conduct disavowals of the conspiracy,” Goldstein said.

Kayatta then asked Goldstein about the advice George gave to Dardinski about a proposed transaction despite insisting that he wasn’t involved. “Isn’t that actually not only not withdrawing, but actually as the lawyer giving advice on how to commit the crime?” Kayatta asked.

“The context is important,” Goldstein said. He said George was acting to appease Dardinski, who is a “concededly dangerous person.”

Goldstein emphasized that Dardinski and Harden had formed their own, independent relationship by the time the transactions at issue happened.

Boston assistant U.S. attorney Mark Quinlivan said withdrawing from a conspiracy requires a full confession to authorities or evidence of an intention to defeat the conspiracy or abandon the enterprise and its goals.

Quinlivan argued that George came up with an alternate plan when he rejected Dardinski’s idea to funnel money through his IOLTA account.

“That is the antithesis of an attempt to defeat or disavow a conspiracy,” Quinlivan said.

Sheri Qualters can be contacted at squalters@alm.com.