voicemail from unknown number said this is officer nikki johnson from the IRS please call us back on this number before we file criminal charges.  No details and the voice was obviously synthesized robotic in nature.

Call from a scammer robo-call claiming to be IRS, Niki, call back or your in big trouble [***]. I recommend that you ignore this call as I doubt the IRS calls work phones.

Oh yeah, Officer Nicki Johnson from the IRS, please return the call before we file charges...
OK, I will call you ONLY if you hold your breathe until I do so.... Get a real life dumb jerk!!!

Caller left a V/M; "This is Officer Nicki Johnson from the IRS/Dept of Revenue. It is in your best interest to return this call immediately before we take action" .
What action? Nope, not calling her back. Ever, never.