I agree with the final comment; I think the DOJ would be well-served by filing something (and that should be pretty tractable, seeing the staggering scope of apparent misdeeds) to extradite SBF as quickly as possible, and then to file amended/superseded charges in the following 12-24 months.
That's likely true.
However, it may also be a more savvy move to let SBF and other execs think little is pending in order to gather more information. Other than reputation of the justice system (which already has a justified slow reputation; "The wheels of justice turn slowly, but they grind exceedingly fine."), this might be the greater consideration...
If they don't rapidly indict, it'll be interesting to see if SBF ever voluntarily returns to US territory before an indictment.
- September 25, 2010: Swartz begins using MIT network to pull JSTOR articles.
- Throughout September through December, a cat-and-mouse game ensues where JSTOR blocks access to certain MIT IPs, and then downloading starts again from a different range.
- January 5, 2011: MIT locates the laptop in a closet that Swartz had been using.
- January 6, 2011: Aaron Swartz is arrested.
- July 11, 2011: Swartz is indicted by a federal grand jury.
Additional indictments followed in November 2011 and September 2012. In Swartz's case, the judicial apparatus moved swiftly. As far as I understand, law enforcement became involved in late December 2010 or early January 2011. The timeline to arrest and indictment was short.
I would expect to see a reasonably quick (i.e. on the order of months) indictment of SBF. While other posters are correct to point out that there's a huge morass of complexity and murkiness around FTX/Alameda, my view is that this creates not one, but several cases -- some of them very straightforward and where I'd surely expect the DOJ to put a preliminary case together in a few months.