What kind of threats? Threats to kill, intending that the person would fear that they would be killed? That was an offence forty years ago, since 1861, in fact. Anything less is out of time for prosecution. And no prosecutor is going to think it worth prosecuting, even so. Even if you had the evidence, that evidence not being used before calls for an explanation, live witnesses, including the defendant, are not likely to have good or reliable memory of the events, and it would not be seen as a case which it is in the public interest to prosecute even in the unlikely event that the chances of a guilty verdict were sufficiently high ( a prima facie case is not adequate; more is needed).
No chance.