And although Walsh was a major backer of the ethics legislation package just before the investigation began, suspicions of his dealings have been floating around the city for years.
Walsh's business transactions have intermingled with the lives of eminent Cantabrigians and colleagues including fellow Councillor Sheila T. Russell, former Police Chief Anthony G. Paolillo and City Clerk Joseph E. Connarton.
The City Council recently voted not to reappoint Connarton to another term because he is aligned with the interests of Independent councillors, according to several political observers.
Walsh firmly denies all allegations of political and financial conflicts of interest, all accusations made by federal investigators and any impropriety in his real estate deals.
"To my knowledge, everything was 100 percent legitimate," Walsh says.
But according to an affidavit submitted by former partner Dennis M. Cargill, Walsh's innocence is questionable.
"Walsh exuded a cocky self-confidence based on his legal/political clout and believed that he could do most anything [in his business deals]," Cargill stated. He also wrote that Walsh's transactions "had serious conflicts of interest."
In addition, rent control activists contend that Walsh's investments in rent control properties have been converted to uncontrolled condominium developments.
"What's been a concern to us is the way in which permits have been removed where [Walsh's] office has been involved," says Michael H. Turk of the Cambridge Tenants Union. "There is a question as to whether there have been illegal removals as well as legal."
Despite a sizable and perhaps growing political faction against the councillor, and despite acknowledgement by councillor and then-Mayor Alice K. Wolf that his dealing may be construed as "possible conflicts of interest," Walsh still maintains a substantial bastion of political support from the big business and Independent sectors.
"He was always a representative of the real estate industry," said Councillor Edward N. Cyr at the height of the controversy. "People vote for him knowing that that's what he does."
And although federal probes into financial wrongdoings of politicians can lead to abrupt endings of political careers, Walsh may be comfortably ensconced enough in the conservative political scene to avoid considerable damage to his base of constituents.
"I do hope to seek re-election," says Walsh. "I will continue to tell my side of the story to the people. And they can be the judge."