For nearly 16 months, New Jersey Gov. Chris Christie has had to swat away allegations from critics -- or chuckle at teasing from voters -- about Bridgegate. Questions about the closing of lanes on the George Washington Bridge in September 2013, apparently by Christie allies out to punish the administration's political enemies, have hung over his attempts to rev up a presidential campaign.

The investigation, led by U.S. Attorney Paul Fishman, appears to be nearing its conclusion. At least one key figure -- David Wildstein, a Christie appointee to the Port Authority of New York and New Jersey -- reportedly will plead guilty soon for his role in creating a weeklong traffic nightmare at the Fort Lee, New Jersey, entrance to the bridge that leads to Manhattan. If Christie himself is not implicated, the Republican governor may be able to escape the cloud of that scandal. Yet some current and former New Jersey officials have raised concerns about the independence of those who are conducting the probe.

Fishman, the federal prosecutor leading the Bridgegate investigation, is in a unique position. New Jersey is one of just five states without an elected attorney general, and its current AG is not confirmed by the state Senate and therefore does not have traditional constitutional protections against political influence. So Fishman -- an appointee of President Barack Obama -- is the state’s only top law enforcement official with a measure of political insulation from Christie.

That’s not the only complication. Fishman is tasked with looking into the administration of a governor who happens to be his predecessor in the U.S. attorney job -- and Fishman is working with an office teeming with holdover Christie appointees. Documents obtained by International Business Times show that Christie hired almost 40 percent of Fishman’s current staff. A full 50 percent of those in Fishman’s office worked for Christie while the Republican was heading the New Jersey U.S. attorney’s office. That includes the head of the office’s criminal division, who is reportedly investigating the so-called Bridgegate affair.

As governor, Christie has hired a slew of officials with their own deep ties to the U.S. attorney’s office. And then there’s the apparent attempt by Fishman’s office to preemptively rule out any suggestion that another New Jersey probe may be looking at Christie.

'An Upstanding Guy'

Fishman’s colleagues and former federal prosecutors interviewed by IBTimes express confidence that he is conducting an impartial review in the Bridgegate case, despite the complicating factors.

“I think he’s one of the smartest attorneys I’ve ever come across,” said Paul Josephson, a partner at Duane Morris and a former a top legal adviser to former New Jersey Gov. Jim McGreevey, a Democrat. “And I think he’s an upstanding guy and takes his responsibilities very seriously.”

Fishman’s spokesman, Matthew Reilly, told IBTimes that “Mr. Fishman is completely satisfied that everyone working on this investigation is doing so with complete impartiality and integrity, consistent with his expectations and those that the Department of Justice demands.”

Those assurances, though, have not tamped down concerns about Christie’s close ties to the prosecutor who is investigating his administration. Christie’s office directed questions about his administration’s ties to Fishman’s office to the prosecutor’s staff.

Last April, Hoboken Mayor Dawn Zimmer released journal entries showing she had hesitated to bring allegations of Christie administration wrongdoing to Fishman’s office because “Christie has friends throughout [the U.S.] attorney's office.” (Last week, the Wall Street Journal reported that Fishman’s investigation into Zimmer’s accusations “has gone quiet.”) Former Hunterdon County Prosecutor Ben Barlyn expressed similar worries in a letter sent to Fishman in December. Barlyn’s case -- which appears to be at an exploratory stage -- involves allegations that the Christie administration quashed local indictments against the governor's political allies.

“I had the same concerns that Dawn Zimmer did -- that the office is conflicted,” Barlyn told IBTimes.

Unlike in a previous case involving New Jersey U.S. Sen. Bob Menendez, a Democrat who endorsed Fishman's appointment, Fishman has not recused himself to let the Justice Department in Washington run the investigation of his predecessor, Christie. That decision is controversial.

“When I was U.S. attorney, if someone asked me to head up an investigation against the U.S. attorney that I succeeded, depending on how close -- I’d be really surprised looking back if I would have done that and not recused myself, only because of appearance,” said former South Carolina U.S. Attorney Bart Daniel, who led a series of major public corruption prosecutions in 1990. “You can’t even have the appearance of impropriety.”

The U.S. attorney’s manual says that U.S. attorneys, or assistant U.S. attorneys, must recuse themselves when "a conflict of interest exists or there is an appearance of a conflict of interest or loss of impartiality."

Overlapping Relationships

Barlyn's case illustrates the overlapping relationships -- and potential conflicts -- at work in New Jersey when such recusals do not occur.

In April 2014, Barlyn first contacted Fishman’s office in connection with allegations, echoed by other former employees in the county prosecutor’s office, that the Christie administration had wrongfully quashed grand jury indictments in 2010 against the governor’s supporters, including ex-Hunterdon County Sheriff Deborah Trout and Undersheriff Mike Russo. Barlyn said he was fired after raising objections.

In June 2014, Barlyn was notified that Thomas Mahoney, a Christie holdover in Fishman’s office, was selected to serve as his point of contact. After six months passed with no word from Mahoney, Barlyn discovered that Mahoney was listed as a potential witness for Trout and her allies at the center of his case, in their wrongful prosecution lawsuit against Hunterdon County.

“When I discovered it, I felt compelled to alert the U.S. attorney’s office that the person they had asked me to contact regarding my serious allegations happened to be a witness evidently for Sheriff Trout,” Barlyn said.

In December, Barlyn informed Fishman of this finding, noting that the New Jersey U.S. attorney's office “has evinced no interest at all in pursuing this matter." Barlyn sent a copy of that letter to the Justice Department in Washington to alert it of possible conflicts.

“I got the response back a few weeks later saying Fishman's office would set up an interview and meet with me,” Barlyn said.

IBTimes reported on the meeting between investigators and Barlyn in February.

Asked why Barlyn was instructed to direct his communications to Mahoney, when Mahoney was a Christie holdover listed as a possible witness for Trout, Reilly -- the spokesman for Fishman’s office -- told IBTimes there was nothing unusual about the situation.

“Mr. Mahoney is the supervisory investigator for our office. As such, he is often the office’s initial point of contact for people who bring complaints or allegations to the attention of our office,” Reilly said in a statement. Mahoney “has no relationship with the former sheriff of Hunterdon County,” he added.

Russo, one of the Christie supporters in the Hunterdon County probe, told IBTimes he didn’t know that Mahoney was listed as a potential witness in his civil case. But Russo said it may stem from the fact that in 2008 he met with Mahoney -- at then-U.S. Attorney Christie’s office -- in an effort to halt the Hunterdon investigation. Russo said Mahoney was "empathetic" and "offered to write something up" to New Jersey state law enforcement agencies, which came under Christie’s control when he was elected governor a year later.

Those agencies subsequently took over the Hunterdon County prosecutor's office and threw out a grand jury's indictments against Russo and Trout. Russo called Barlyn “a fraud.”

'We Talk To People All The Time'

After Barlyn raised concerns about independence and threatened to go to the Justice Department's Public Integrity unit in December, Fishman sent two federal investigators to meet with him. But Fishman’s office was quick to defend the governor, issuing a statement seeming to preemptively rule out that Christie himself was being looked at in connection with the quashed indictments in Hunterdon County.

“Any characterization that we are investigating the governor about this is just not true,” Fishman’s office told MSNBC after his staffers met with Barlyn. “[W]e talk to people all the time. It doesn’t mean we’re investigating anybody.”

ABC News subsequently reported that “sources familiar with the investigation” confirmed there is an investigation “examining the conduct of other current and former members of Christie's gubernatorial administration.”

Former U.S. attorneys interviewed by IBTimes questioned the attempt by Fishman’s office to parse or downplay the language used to describe the probe.

“If [law enforcement] is talking with somebody, it’s an investigation,” said former U.S. Attorney Kent Alexander, an appointee of former President Bill Clinton. “If someone is going to speak with somebody, by definition, I always think of that as an investigation.”

Attempting to rule out Christie from the probe, he added, is “unusual” because “you are speaking for all of law enforcement and you are really foreclosing the possibility of going after them later.”

Michael McKay, an appointee of former President George H.W. Bush who served as the U.S. attorney in Washington state, agreed, saying it is “imprudent” to preemptively rule someone out of a probe.

“An investigation is like a long piece of string and you pick up the end of the string and you start to follow it. You don’t know where it’s going to lead you,” McKay said.

The pronouncement from Fishman’s office that Christie isn’t under investigation, and a leak to NBC News from “federal officials” asserting that the federal Bridgegate investigation had not uncovered any evidence against Christie, Barlyn said, have led him to question “whether the U.S. attorney’s office in New Jersey would be inhibited from aggressively investigating my case.“

Christie Appointees Involved

Mahoney, who is also reportedly involved in the Bridgegate probe, may not be the only Christie holdover still involved in inquiries related to his former boss. Tom Eicher, who now leads Fishman’s criminal division, was appointed to the U.S. attorney’s office by Christie in 2003. Eicher does not appear to have recused himself from the investigation into the man who gave him his job: A Main Justice report last year said that Eicher is one of several top staffers whom Fishman was consulting before making decisions in the Bridgegate case.

Reilly, Fishman’s spokesman, said the Main Justice report, about which staffers are working on the Bridgegate investigation, was “wrong,” but did not directly dispute any elements of the report or its assertion that some Christie holdovers are working on the Bridgegate investigation.

“We generally do not discuss who is working on specific investigations or matters. The ultimate decision on who is assigned and what resources are allocated is made by the U.S. attorney,” Reilly said. He reiterated that Fishman has full confidence that his staff is investigating with “impartiality and integrity.”