The number of individuals facing federal charges in the ongoing San Francisco City Hall corruption scandal rose to eight this week, as two local businessmen were charged with bribing former Department of Public Works Director Mohammed Nuru.

As NBC Bay Area reports, Alan Varela and William Gilmartin III, the president and vice president of Oakland-based construction firm ProVen Management, have been accused of bribing Nuru with expensive dinners, and a tractor valued at $40,000 for Nuru's Colusa County vacation property. Much as with earlier charges and revelations in this scandal, a lot of things lead back to this ranch Nuru was building/fixing up in Stonyford, California, for which multiple individuals with city contracts allegedly donated labor, materials, and other gifts.

Nuru also seems to have spent years dining out on other peoples' dime, and he likely ate and drank very well across foodinista San Francisco over the years. As one prosecutor says in the federal complaint, "I estimate that Gilmartin spent in excess of $20,000 on meals with Nuru using a ProVen company credit card."

Varela and Gilmartin are accused of seeking a backroom deal to build an asphalt recycling plant on Port of San Francisco property, after allegedly being supplied insider information on the bidding process by Nuru. The pair apparently did this with the help of Balmore Hernandez, the CEO of construction company AzulWorks and another defendant in the federal probe.

"Instead of awarding public works contracts on the basis of merit, the defendants allegedly sought to secure significant profits on the basis of bribes and backroom deals," said U.S. Attorney David Anderson in a statement Thursday.

These latest charges add to the list of individuals ensnared in the widening federal probe, which was first revealed with the arrests of Nuru and co-conspirator and local businessman Nick Bovis in late January. The investigation has focused on what city insiders and others have often referred to as the "low-level" and "pay-to-play" corruption that has allegedly run rampant in some city departments for decades, and so far charges have mostly been leveled against local businesspeople and a few city employees without major name recognition.

As the Chronicle reports, Hernandez, whose relationship with Nuru dates back to his days as a DPW employee, has recently pleaded guilty in the probe and agreed to cooperate with federal prosecutors. Hernandez is accused of gifting Nuru with more than $250,000 in free labor and construction materials for his vacation home. Another defendant, local contractor Florence Kong, has also pleaded guilty to bribing Nuru — with a Rolex and a free gate for that vacation home — but is not cooperating with the investigation. Both Hernandez and Kong were charged back in early June.

Siddhartha Patel, assistant special agent in charge at the FBI in San Francisco, issued a statement saying, "While our investigation is ongoing, I hope the resolutions in the Hernandez and Kong cases will help restore confidence in our city governments for Bay Area residents."

Per NBC Bay Area, Varela issued a statements to the employees of ProVen claiming innocence, and saying the tractor was merely a loaner to Nuru.

"The government has also falsely accused us of attempting to influence Mr. Nuru to award ProVen a contract to build and operate and asphalt recycling plant and concrete plant for the Port of San Francisco," Varela wrote. "In fact, the contract was awarded by the Port of San Francisco, an independent body, and was based on an objective point system in which the score for ProVen's public bid was almost twice the nearest competing bidder."

Still, this could be detrimental for ProVen's business with the city, as Hernandez's firm, AzulWorks, has been banned from eligibility for future city contracts following administrative disbarment proceedings begun by the City Attorney's Office in July. Those proceedings began prior to Hernandez's guilty plea.

ProVen, which has worked on a number of large public projects including one at the Bay Bridge toll plaza, has reportedly received $25 million in payments from the City of San Francisco in the last five years, including $7 million from Nuru's former department.

Previously: FBI Probing Whether City Hall Power Couple Directed Contracts to the Person Who Sold Them Their House

Photo of Nuru via Department of Public Works