Federal prosecutors are beginning to wrap up their case in the trial of two Boston City Hall officials accused of extortion.

City tourism and entertainment director Kenneth Brissette and inter-governmental affairs director Timothy Sullivan, both senior appointees of Mayor Marty Walsh, are accused of illegally pressuring the Boston Calling music festival into hiring union labor in 2014.

Among witnesses to testify for the prosecution Thursday was Bill Kenny, whose entertainment production company was hired to run Boston Calling's fall 2014 concerts.

Kenny testified to having had all the staff he needed when, in the days before the festival was to open on City Hall Plaza, Boston Calling CEO Brian Appel told him he’d have to take on some union stagehands.

Appel has testified he made that call after feeling pressure from the defendants.

Kenny didn’t want extra workers — but testified that he hadn’t felt the festival was being extorted.

Those comments echo testimony by Appel himself, in which he acknowledged under cross-examination that while he felt pressure from the defendants to hire union stagehands, there were no threats and he had not felt either defendant meant to harm him or his company.

Also taking the stand Thursday, former senior Walsh aide Joe Rull.

Rull was the second senior Walsh staffer to take the stand in this trial as a witness called by the prosecution. Joyce Linehan, an advisor to Walsh, testified earlier in the week to having alerted Walsh to the fact that Boston Calling was having conflict with the Local 11 stagehands union and that defendant Brissette had told its executives "they'd have to hire a few guys," according to an email Linehan wrote to Walsh.

Both Linehan and Rull testified to having been granted immunity for their testimony; though on the stand, Rull said he felt he hadn't needed it because he had done nothing wrong.

Under questioning by the prosecutions, Rull testified to a conversation with Brissette in 2014, prior to the events surrounding Boston Calling.

At the time, Rull testified, the reality show Top Chef was filming in Boston, and had filmed a segment featuring Mayor Walsh.

At the same time, members of the Teamsters union were angry with the show for refusing to hire union labor and were threatening to picket.

Around that time, Rull testified, Brissette approached him in City Hall looking “like someone who had been caught under-age drinking by his parents.”

Brissette, Rull testified, was seeking Rull’s advice on how to deal with the fact that the Teamsters would likely be upset to see Walsh, a pro-union mayor, appearing on a show they had been picketing.

“He told me he’d F’d up,” Rull said, “and told me he was going to try to fix it … and he mentioned potentially pulling the permits or pulling the footage,” featuring Mayor Walsh, Rull recounted.

Rull said he told Brissette that pulling the show’s permits in the circumstance would be “illegal.”

Prosecutors are clearly hoping Rull’s testimony will bolster their case that Brissette, along with defendant Sullivan, were willing to use city permits as leverage to pressure Boston Calling into hiring union labor.

But during cross-examination, Rull agreed with lawyers for the defense that Brissette had been asking his advice in the moment, and had, after Rull’s warning, seemingly dropped any plan to pull or withhold permits for Top Chef.

Rull agreed with defense lawyers that Brissette was new on the job and had made “a rookie mistake.”

Meanwhile, the defendants are accused of extorting Boston Calling – not Top Chef – and Rull had far less to say about the defendants’ interactions with that production.

Defense lawyers also hammered at one of their central contentions in the case: That Brissette and Sullivan were merely doing their jobs in trying to broker a resolution to a labor dispute that threatened to turn nasty.

“You would often meet with constituents?” asked defense attorney Bill Kettlewell.

Rull: “Anyone and everyone,” Rull replied.

Kettlewell: “That was part of your job?”

Rull: “Yes.”

Kettlewell: “It was part of everyone’s job?”

Rull: “We were asked to have an open door.”

A few moments later, concerning growing tension between the Local 11 stagehands union and Boston Calling:

Kettlewell: “Mayor Walsh’s policy [was] to bring people together, get them to the table, and have them try to work something out?”

Rull: Yes

Kettlewell: Did that happen?

Rull: “Ultimately, yes.”