A blackmail letter is being sent to people in Santa Clara County threatening to unveil illicit activity connected to the recipient.

And the scammers are demanding thousands of dollars in Bitcoin to keep quiet.

Investigators with the Santa Clara County District Attorney’s Office say the Bitcoin demand is likely because the cryptocurrency is virtually impossible to trace.

The letters are landing in mailboxes across the county, but the DA warns they are a scam.

“This is one of the most