Whoever "Bob" is above I believe is part of the scam, just an example of how these people operate. Don't take the call and put it on your do not call list. If the IRS is trying to contact you it will not be by some odd phone number from Washington State, they will send you mail through the postal service. There is not such thing as a "Pre-audit data base" from the IRS.
Modern technology has given telespammers the tools to call you.
Lawbreaking telescammers ignore both the Do Not Call list and any request you might make.
Modern technology can also protect you, if YOU do a few simple things!
The most effective thing to do is to get a call blocking device, service or app.
Then, use it correctly.
Google "call blocker" for more information. There are available apps (some free) for smart phones, and services and devices for landlines.
If you cannot use or afford such a tool, then:
• Do not answer calls from unknown numbers ... let them go to voicemail or answering service. Telespammers usually hang up after 3 or 4 rings.
• Do NOT return calls from unknown numbers! All that does is verify your phone number, and make it more valuable to more spam groups! And, in some cases, those return calls may cost $20 or more to complete. If the incoming call was important, they would have left a message!
• If you have a "dumb" cell phone, assign the scammer's number to a group named "scam" (or similar). Then, assign a silent ringtone to that group. (This also works for smartphones). The spammer will usually hang up before the phone goes to voicemail.
• Another option, for cell phones: Assign a "silent ringtone" as DEFAULT. Then, assign your favorite ringtones to all known friends / family / business numbers. That way, you will hear rings ONLY from those you wish to contact! You will not hear scammers' rings, even if they change their number! (This is also called "whitelisting", and will cause you to miss calls from non-whitelisted numbers).
If you want to report potential fraudulent or scam calls, here are two pages of links to (mostly government) sites in Canada and the USA were you can report those scams, or learn more about them.
Look here first:
http://800notes.com/arts/I2neMkbUAAo/where-to-report-phone-crime
If the reporting site you wanted is not in the above list, try this one:
http://phonehelp.2truth.com/complaint_sites.html