Nah federal police agencies would be involved. If real intelligence agencies gave half a shit about SR it would be long gone, and anyone they wanted busted on it would be busted, customer or vendor. They don't concern themselves with SR level traffickers, and half the times they concern themselves with drug lord sized traffickers it is to carry out mutually beneficial smuggling operations with them.
Federal police do intelligence operations but are generally not considered intelligence agencies, other than maybe FBI. Intelligence agency is more like CIA, NSA, etc, federal police are more like ICE, DEA, etc. FBI is kind of a hybrid post 9/11. But even some local police agencies have intelligence units these days. And really traditional police work is essentially the same thing as human intelligence, they just are generally more restricted by the law in regards to what they can do. For example CIA HUMINT it is probably standard procedure for a sexy agent to fuck someone and start a relationship with them to covertly spy on them, but it is generally frowned upon for local police department to do such things in their undercover operations, although it has happened before (undercover police have started families with surveillance targets before....but it isn't standard procedure).
One of the characteristics of Local LE / Federal LE / Intelligence agency post 9/11 is the bluring of lines between these things though. This is generally recognized by libertarian minded people as 'not a good thing'. DEA has a massive international signals intelligence arm, but I dunno if it would be correct to consider them a SIGINT agency. I also tend to imagine that they are about as l33t at SIGINT as the FBI apparently is.
http://publicintelligence.net/wikileaks-cables-show-dea-has-become-international-spy-network/
http://federatedit.com/services/analyticsupport/dea-sigint
Project Profile – DEA Signals Intelligence Collection and Analysis (DEA SIGINT)
Federated provides expert and experienced Analytic services in the realm of collecting, analyzing, and reporting Signal Intelligence (SIGINT) data through the interception of information promulgated via radio and electronic transmissions. In this effort, Federated personnel monitor, translate, and interpret real time bi-lingual exchanges over related communications equipment such as High Frequency direction finding devices. Based on the raw data extrapolated from various transmissions, our team utilizes qualitative applications of this information and details these findings in tactical actionable intelligence reports. These reports are distributed in an interagency effort that includes Law Enforcement Agencies (LEA), Department of Homeland Security (DHS), Intelligence Community (IC) partners and Department of Defense (DOD) organizations to advance and promote shared missions.
Federated also contributes to the mission through temporary duty deployments to foreign and domestic locations in support of this operation. Throughout these operations, the duties performed include the conduct of communications intercept operations, site assessments, radio frequency evaluations and the testing of advanced technical equipment in mobile and fixed locations. Our Analysts have received 8 Superior Performance Awards, 7 Special Awards for “Life Saving Actions” and 22 Letters of Appreciation for their timely and accurate analysis of intercepted communications that directly led to thwarting transnational threats.
If the DEA actually had really good SIGINT people working for them, it would be safe to say that they can trace hidden services and do some serious damage against Tor. But even if they have the best people working for them, access to signals matters too. NSA can gather signals from IX's for their analysts, but DEA analysts would not have such access and would need to resort to other signals gathering techniques. So skill isn't the only thing involved, so is the ability to position yourself to gather signals in the first place.