Received two calls about 30 minutes apart from this number; both showed "Wireless Caller" on my Caller ID. Both left an automated voicemail using a computer-generated voice, but only the last few seconds were recorded: "...to learn more about this case number, please call immediately..." Tried calling the number back and a man answered speaking in broken English with an Oriental-sounding accent. Announced himself as "Officer ____ (couldn't understand the name) with Investigations Department of Internal Revenue Service" and asked if I he could help me. I stated that I had dialed the wrong number and hung up. Assuming he was trying to get me to pay some sort of taxes or tax penalty I don't owe.