USA - Can DEA moniter SWIMs text messages?

[Herbal Healer 019]

Ok SWIM is a bit freaked out right now...SWIM received a text message on sat. from Nobody@kansas.shawnet.com the message read Subject: Free SMS 1@AnonymityAcquired.com ...This is the DEA we have reaason to believe you are involved with dealing and/or smok...thats all it said now SWIM went to both sites mentioned in the text and found that anonymityaquired can be used to send free texts and on the site it stated:
"We know that you are tired of paying text messaging fees. That's why you can now send free and anonymous text messages to any USA cell phone provider. Its 100% free texting, with no catch! You can even prank your friends! Your friends will never know who sent them the text message! We offer spam free text messaging, meaning we will never send you unwanted text messages or share your cell number with anybody. What are you waiting for? Stop spending and start texting for free!"
....Shud SWIM b worried???????? plz respond ASAP