Many of today’s scams involve people impersonating government officials or officers of law enforcement agencies. Customers are frequently contacted by scammers posing as representatives of the Social Security Administration, the US Marshals/local police, and the IRS (especially around tax season).
No government organization will ever contact you to request Bitcoin or cryptocurrency for any reason! Bitcoin is not recognized as an official currency by the US government or any other governmental organization. Police or agents of law enforcement organizations will never call you directly and threaten you with arrest, demand money, or promise to keep your funds safe as cryptocurrency.
Anyone who contacts you with such claims should be ignored and reported to local law enforcement because they are a scam.