Chris Christie’s bravura press conference performance on Thursday, in which he apologised to the citizens of New Jersey while simultaneously blaming others for the “Bridgegate” scandal that has engulfed his office, has temporarily contained the crisis, but is unlikely to put an end to the scandal.

The New Jersey governor faces challenges on several fronts flowing from this week’s revelation that several of his aides engaged in an act of political revenge that snarled traffic for thousands of people and even put the lives of some of the state’s citizens in danger. Several official investigations are already underway, including one by a federal prosecutor’s office, which is exploring the possibility that criminal offences were committed.

The continuing distraction of the events of last September, when two access lanes onto the George Washington Bridge from the nearby small town of Fort Lee, New Jersey, were diverted, prompting days of traffic carnage, is certain to sap the governor’s office of energy at a particularly sensitive time for him. Christie, who won a convincing re-election victory in November, had been expected to spend this year laying the foundations for a bid for the Republican presidential nomination in 2016.

Atop the pile on Christie’s in-tray of potential troubles is the seething anger among the 35,000 residents of Fort Lee who endured the misery of traffic caused by the lane closures. On Thursday afternoon, he travelled to the town in order to apologise in person to its mayor, Democrat Mark Sokolich, as the decision to close the lanes was made because Sokolich was the target of a political vendetta by Christie’s staff after he declined to endorse the governor for re-election.

Christie said the “very good conversation” he had had with Sokolich had been productive, even though, ahead of the meeting, Sokolich had expressly asked the governor not to come to his town. The mayor had said he was not yet ready to accept a visit, and wanted to see if more details emerged from the on-going investigations.

Those investigations raise another potentially perilous problem for Christie – the key players in the scandal, who have so far stayed mum, but whose continuing silence is not guaranteed. In his remarks on Thursday, the governor said repeatedly that he had not known that members of his staff had been behind the lane closures until emails exposing the roles they played emerged on Wednesday. If any of his former aides decide to publicly contradict him, the ensuing fallout could prove disastrous for the governor.

The two former Christie officials most closely associated with “Bridgegate” are Bridget Kelly, his former deputy chief of staff who was sacked on Thursday and David Wildstein, his appointee to the Port Authority – the entity that controls the bridge – a post from which resigned last month.

They were revealed to have been key instigators of the lane closures, with Kelly saying in an email: “Time for some traffic problems in Fort Lee”, and Wildstein replying: “Got it.

David Wildstein and Bridget Anne Kelly. Photograph: Reuters Photograph: Reuters

Christie said that, though he fired Kelly, he has not yet spoken to her to ask for her explanation of her actions, explaining that he was “quite frankly not interested in the explanation at the moment.” It remains to be seen whether Kelly could cause further discomfort for the governor should she decide to go public in the wake of her dismissal.

Wildstein has also yet to give his account of events. On Thursday, called in front of the transportation committee of the New Jersey state assembly under subpoena, he consistently invoked the Fifth Amendment, which allows witnesses to remain silent so as to protect themselves against self-incrimination. Towards the end of the hearing, the committee voted to hold him in contempt, and police have been asked to consider pressing misdemeanor charges.

Lawmakers say they will continue to try and prise testimony from Wildstein, but they will have a tough court fight ahead of them as they do that.

The assembly’s investigation is just one of several already underway. The most potentially threatening to Christie is one being conducted by the office of the US Attorney for New Jersey, which announced on Thursday that it is studying whether any “federal law was implicated”.

Civil lawsuits are also possible after it emerged on Wednesday that several people had been adversely impacted by the lane closures. Emergency vehicles, including ambulances, became tangled in the gridlock and took almost twice as long to reach injured and ailing people as they would have in normal circumstances.

Jim Cohen, a professor at Fordham law school, said that Christie will be able to claim immunity from any civil action. “But any law suits would be sure to keep this issue in the public eye, which could be difficult for him,” Cohen said.

Part of the risk posed by “Bridgegate” for Christie is the impression the scandal gives that he is a vindictive leader prone to bullying – a suggestion that runs counter to the image he has carefully tried to cultivate, of a bi-partisan politician able to appeal to all Americans. The governor remains vulnerable to any new evidence of overweening behaviour.

On Thursday, the mayor of Jersey City, Democrat Steven Fulop, put out a statement in which he echoed the complaint of political retribution following a decision not to endorse Christie for re-election. Over six months, he said, city officials’ persistent requests for meetings with state commissioners and the Port Authority had been rebuffed.

An entire day of meetings with state commissioners had been cancelled “within an hour of the time I communicated my intention to not endorse,” Fulop said in the statement.