"Truecaller" app indicated call came from Oscar Cruz in Washington DC. A female voice recording left a voicemail on my cell phone saying it was the final call from the IRS and, like previously reported, I was to call them immediately about the lawsuit filed against me.
I received a missed call with voicemail from this number stating it was the IRS as well and that this was their last attempt to reach me before filing a lawsuit, as well as the same callback number listed. Caller ID showed it was a Washington DC #. This has to be a scam, as the IRS doesn't leave phone calls, they send letters.