Mark Wahlberg, Josh Duhamel and WWE superstar Roman Reigns don't have to worry about a DEA probe into their alleged ties to a steroid dealer ... because the law is on their side.
Law enforcement sources tell TMZ ... the 3 celebs -- who were named in a phone interview of imprisoned steroids dealer, Richard Rodriguez -- won't be investigated by the DEA because the agency doesn't target alleged buyers of illegal drugs.
Instead, the DEA focuses its efforts on going after kingpins like Rodriguez -- along with other traffickers, manufacturers and distributors.