Goldman Sachs in an American bank, headquartered in New York City. The bank is subject to the laws of the US, and of New York.
The events "happened in Malaysia" only in some very abstract sense that some key players may have been located in Malaysia at some points. The bank though, concretely, remains an American bank throughout. Nobody is going to tell a court that oh, this was actually a Malaysian thing, it's OK for American banks to be corrupt so long as somehow Malaysia is involved, that's fine...
Malaysia was way more involved than that. The money in question comes from Malaysian tax payers, and the former prime minister Najib is under arrest because it looks like he channeled $700m of it into his own pockets.
It is a federal felony for an American citizen to bribe a foreign official in the course of doing business. Especially if that business involves a company regulated by the SEC.
If I'm reading this right it's because the journey the money took while being laundered went through several US financial systems and was orchastrated by the US branch of Goldman Sachs.
Or it may just be the fact that some of Jho Lows property being seized is on US soil, and hence is under the juristiciation of US law enforcement; this whole thing is kinda hard to follow.
