"Don't touch me!" Anderson yelled. "I'll kick your ass."
City staffers watched awkwardly as the confrontation continued down the hall to the elevator.
"You're doing this because I'm a Republican and a Bush supporter," Hansen charged.
"You are absolutely out of your mind," Anderson, a Democrat, rebutted. "Sue me."
Moments later, after Hansen grabbed Anderson by the arm, the mayor and the principal for Wasatch Property Management had to be restrained by Anderson's chief of staff and two Wasatch employees - as a security guard looked on anxiously.
The near fisticuffs erupted after a tense redevelopment agency meeting, where Anderson asked the board to revoke $1 million in parking-garage money previously allotted for a planned office tower at 222 S. Main St.
Anderson insisted Hansen has not been an honorable business partner for the city. Since 2003, the mayor alleged Hansen has cheated the RDA - refinancing an RDA loan for the Wells Fargo building without proper disclosure.
Hansen also has improperly claimed interest offsets worth more than half a million dollars by twisting an employee-tenant agreement at the bank building, the mayor claimed.
Hansen labeled the accusations a "malicious attack" and "absolute malignment," later (in the hallway) calling Anderson a "filthy liar."
As a pre-emptive strike, Hansen announced to the RDA board that Wasatch has pulled out of the financing deal with Hamilton Partners for the Main Street office tower.
"We thank Rocky for inviting us to leave Salt Lake and enter other cities that are much more amenable," he said.
Now, Hamilton likely will have to seek another partner to get the planned tower - it was scheduled to break ground this fall - off the ground.
Before leaving - and chest-bumping the mayor - Hansen handed deputy RDA Director Valda Tarbet a check for $586,000, half the amount of the RDA loan for the Wells Fargo building.
The 2003 agreement, Tarbet notes and documents show, calls for Wasatch Property Management to immediately reimburse the RDA half the loan amount should the developer refinance for a term longer than three years.
D.J. Baxter, the city's new RDA director, notes the Wasatch refinanced a five-year loan two years ago, but just disclosed that to the city on Monday.
"That money would have been available for any number of projects," Baxter explained minutes after Hansen left City Hall and Anderson had returned to his office. "It harms the RDA. There's interest owed on that money."
Baxter says he encourages developers like Hansen to invest in the city, but expects the terms of agreements to be honored.
For his part, Anderson says if Hansen takes his money outside Utah's capital "it would be great. It would be a good thing for our city."