Ex Commited Social Security and IRS Fraud

My question involves criminal law for the state of: Mo My ex was drawing SS disability from 2002 through 2006. During this time, he was also sub-contracting, and contracting roof jobs under the table.
Social Security became suspicious after a number of anonymous fraud report calls. They couldn't find the proof that my ex was purposely commiting fraud because my husband was having the checks put in my 19 year old son's name. My son is his step-son.
Well, the kicker is, that the contractor that my ex was roofing with filed taxes on the roofs. This was something my ex wasn't planning on. $63,000.00 was on the tax papers. Inorder for my ex to continue to cover his butt, he exscorted my son to the CPA office and pretended to be a concerned parent helping his son out with his taxes. This was in 2006, and till this day, the tax papers are done, but still waiting to be picked up at the CPA. I told my ex a couple months ago that I wanted him to make things right. And what he did was WRONG! I feel very bad for my son even though he should have known this was wrong. My ex called me a ----- snitch!
I'v contacted my local SS office, the criminal IRS investigators in California, The Department of Revenue, and left my full name, and alot of details. I'm hoping they nail him on this! This would be considered a Fed crime wouldn't it? I feel bad for my son because my ex was a controlling person, my son is very gallable.What do you think this might lead to?

I wonder if the feds will take this seriously, and do something about it? It's been a week since I contacted the different agencies. I haven't heard anything yet.