There were two WSJ articles on this one now behind a paywall that read like Evercore was hired in the spring -- Fisker also hired RBC bank to look for private debt financing last spring under the ex-Chrysler CEO.
Two of Advanced Equities top partners were sanctioned by the SEC for the Bloom energy raise but the SEC did not shut them down directly. Advanced Equities had a reasonably large payroll and burn rate and got a capital call in October. Probably they hadn't been able to get in on any new deals since the summer SEC ruling and none of their old deals had a successful exit yet. e.g. BrightSource Energy (thermal solar plants in California desert) seems to be progressing OK but canceled their IPO last spring because institutional investors didn't want to buy in until they saw the plant finished and running on budget. The IPO would have been on the day natural gas bottomed below $2 (it's almost $4 now). I don't think it really matters to Fisker whether or not Advanced Equities shut down because that particular investor network was pretty tapped out. Fisker needs to be and are looking elsewhere for funding.
Unlike some of the famous public brokerage shutdowns like Peregrine Financial (PFG) and MF Global who commingled customer funds and lost those funds during capital calls, Advanced Equities setup separate LLCs for all their investors who are thankfully not otherwise affected by the cap calls.