If you commit a federal crime, such as robbing an FDIC insured bank, you will usually do time in a federal prison. But I know of one case where that didn’t happen. The man was charged with robbing 52 commercial banks over a four year period. The FBI figured he’d nabbed a total of $3.5 from banks all over the country. All the while, the man had been putting a portion away for a defense fund for when he would eventually get caught.
By the time they got him, he had close to a million dollars in the fund and was able to afford a top notch lawyer. The man had a clean criminal record before this and had come home from three tours in Vietnam a bemedaled Special Forces veteran. In the end, they were only able to convicted him of one bank job and a deal was made for him to do 2 to 5 in a state prison. He wanted state time because it was easier than fed time and he got it.
He did two years in a state facility, went out on a three year parole, went underground within a year, ended up on a sailing yacht in the Caribbean with a buxom French girlfriend, and died of a heart attack at sea a few years later.
That is the only case I’ve ever heard of where someone committed a federal crime and did state time.