Two prominent government watchdogs are calling on the Massachusetts Ethics Commission to investigate additional real estate deals involving former Boston official John Lynch, who is set to plead guilty Thursday to accepting a $50,000 bribe from a developer. Those calls come after a WBUR review of land records found that Lynch purchased or became the trustee of four properties that benefited from a city loan program.

In one case, Lynch struck a deal with a retired Boston police officer whom Lynch’s city agency loaned $11,600, at zero interest, for roof repairs. Shortly after receiving the loan, the retired officer sold the rear half of his property to Lynch, who used the subdivided lot to build the house where he now lives, in the Clam Point neighborhood of Dorchester.

In another case, Lynch paid roughly 20% less than assessed value for the home of his deceased next-door neighbor. That neighbor had several years earlier received a $25,000 interest-free loan for roof repairs and new windows from Lynch’s agency. After buying the home in 2015, Lynch then successfully petitioned Boston’s Zoning Board of Appeal to waive a restriction on two-family homes so he could raze the late neighbor’s house and build a duplex.

He ultimately sold the duplex’s two units for almost $1.5 million, combined — more than seven times what he paid for the property.

"There's a lot of smoke in the sequence of events," said Pam Wilmot, executive director of Common Cause Massachusetts, a nonprofit focused on government accountability. "Whether there is fire, or a violation of the law, [it] needs to be pursued in more detail, and that's what the state ethics commission does."

Former Massachusetts Inspector General Gregory Sullivan also said the ethics commission should investigate.

A commission spokesman said he "cannot discuss actual situations and can neither confirm nor deny whether the commission will investigate any matter." According to its published guidelines, the commission does not make investigations public unless it finds "reasonable cause to believe that a violation has occurred."

Lynch's attorney, Hank Brennan, did not respond to written questions about the real estate transactions.

Lynch, 66, has agreed to plead guilty to federal charges of bribery and tax fraud, and resigned last month as assistant director of real estate in a division of the Boston Planning and Development Agency. According to court documents, his long career in city government included more than two decades in Boston's Department of Neighborhood Development, which offers interest-free loans for home repairs to residents who meet age, income and other conditions.

Such a loan "has no monthly payment and does not become due for repayment until the owner sells or transfers ownership of the property, or undertakes a

cash-out refinance of the home," according to the city.

Prosecutors say a developer paid Lynch to influence the vote of a zoning board member in May 2017; when the vote went as hoped and the developer turned a profit on a South Boston property, Lynch collected a $50,000 payoff.

Court documents do not identify the zoning official allegedly influenced by Lynch, but one board member, Craig Galvin, resigned over the weekend. Mayor Marty Walsh last week directed the law firm Sullivan & Worcester to review the city's Zoning Board of Appeal process and hired Brian Kelly, the former head of the public corruption unit within the U.S. attorney's office in Boston, to interview every board member, including Galvin.

In addition to supporting the South Boston project on which Lynch accepted a bribe, Galvin voted in favor of Lynch's Clam Point duplex project five months earlier. Galvin's real estate firm then acted as the property's listing agent, a role that typically draws a commission.

When Lynch sought zoning board approval for the duplex at a hearing in December 2016, he assembled an A-team to help make his case. City Councilor Frank Baker, who calls Lynch a friend, and the Mayor's Office of Neighborhood Services sent representatives to speak in support of the project. Video of the hearing is archived on the board's site.

Dressed in a tan blazer and light blue button-down, Lynch sat silently beside his architect, James Christopher, the son of William "Buddy" Christopher, who was then the commissioner of Boston's Inspectional Services Department, the agency in charge of permitting.

William Christopher, now a special adviser to Walsh, is on leave while lawyers hired by the city probe the zoning board. He was the original architect on the South Boston project at the center of the bribery case against Lynch. He told The Boston Globe he was stepping aside "so as not to interfere with the inquiry."

It is not uncommon for people requesting zoning waivers to hire well-connected architects or to seek the backing of City Hall officials, but Lynch's strategy appears to reflect a political savvy acquired over decades in city government.

After Lynch agreed to plead guilty, Walsh said that his administration is committed to “level the playing field in the development process.”

When Galvin voted for Lynch's duplex project, he did propose one caveat — the design would be subject to review by the Boston Planning and Development Agency, where Lynch was an official.

In response to a WBUR inquiry, the planning agency said it will review conflict-of-interest policies that may have applied, and whether they were followed.

John Lynch, left, petitioned Boston's Zoning Board of Appeal in 2016 to allow him to build a duplex on a lot where two-family homes are normally prohibited. He was joined by architect James Christopher, whose father ran the city's Inspectional Services Department at the time. (Video still)

Land records do not show whether Lynch had a direct role in the city's issuing of loans on the properties he later acquired or controlled as trustee. The loan recipients are all deceased.

"There's an appearance here that an official inside of a public entity wound up as a beneficiary of loans that were made by the entity, and that's what should be investigated in this case," said Sullivan, the former state inspector general who is now research director of the Pioneer Institute, a public policy think tank in Boston.

One of the loan recipients, Catherine Flannery, used a low-income housing program administered by the Department of Neighborhood Development to purchase a house and adjacent lot in Dorchester that the city had seized from previous owners because of unpaid taxes. Flannery also received loans totaling $28,523 from the agency for “necessary capital improvements and rehabilitation," according to records.

"Probably it was through John that Catherine was able to buy that house," said Jose Barros, a community organizer and planner at the nonprofit Dudley Street Neighborhood Initiative, where Flannery was a board member, according to her obituary.

Barros said he helped care for Flannery, who died in 2015, and "she mentioned John many, many times." Barros said he "saw that there was a lot of trust" between Flannery and Lynch.

Records show that near the end of her life, Flannery transferred her two properties into a living trust, with Lynch as the sole trustee. Acting on behalf of the trust, Lynch sold the properties to Barros' daughter. Barros said he negotiated the sale with Lynch.

It is unclear whether Lynch collected fees for brokering the sale or managing Flannery's trust.

Barros expressed surprise at the charges against Lynch.

"I can only say good things about the few times that we spoke or met," Barros said.