Just report these calls to the Federal Trade commission under the Do Not Call website. Threatening folks is illegal. Sooner or later they will be caught and brought to trial and fined or jailed. No sense in reporting to the local police nothing they can do.
I called back the number from a blocked number to screw with them because I know it’s a scam and pretended to be frantic that I just received a message telling me I was going to be arrested. The guy told me to go “f*ck” myself. I hope the FBI locates and charges these predators and that they rot in hell trying to scam the elderly!!!!