In the middle of a story about a masked US Marshal who was injured in an operation against the cartels in Mexico in July, Devlin Barrett reveals what was obvious, but never confirmed, at the time. US Marshals (and other US personnel) were involved in the operation that nabbed Chapo Guzmán.

The Marshals Service operations in Mexico are carried out by a small group sent for short, specific missions. The goal is to help Mexico find and capture high-value cartel targets.

One operation yielded a great success: The capture of cartel boss Joaquin Guzman Loera, known as “ El Chapo, ” earlier this year. It is unclear whether U.S. Marshals personnel were disguised as Mexican military men on the day he was caught.

Sometimes the Marshals Service targets a person Mexico would like to apprehend but who isn’t wanted by U.S. authorities, the people familiar with the work said.

Marshals personnel on the ground dress in local military garb to avoid standing out and are given weapons to defend themselves.

The reason I was pretty certain at the time Americans were involved was because all of the “Mexican Marines” involved in the operation — at least the ones that showed up in pictures — were fully masked, so fully that they likely hid light hair as often as faces that might get people targeted by the cartels.

Barrett also makes clear that the toys the Marshals are using in the US under Pen Register authority are also being deployed when they work under cover in Mexico.

The Marshals Service works closely with the Mexican Marines because the U.S. agency has expertise at finding fugitives, in part through technology that detects cellphone signals and other digital signatures. That includes airplane flights operated by the agency carrying sophisticated devices that mimic cellphone towers, as reported last week by The Wall Street Journal. That technology works better with a ground presence.

[snip]

The people familiar with the matter described the Marshals Service as a police agency affected by mission creep. More than five years ago, the Service flew small planes along the border to detect cell signals and locate suspects inside Mexico. About four years ago the flights crossed deep into Mexican airspace, the people said.

They added that, more recently, some flights have been conducted in Guatemala.

I would bet that the tech deployed against Chapo was even niftier than what the Marshals use here. That would allow them to test nifty new technologies against the most hardened targets, and do so without any legal niceties required, before they start conniving judges to authorize the same technologies against easier targets here. So if we look closely at the Chapo operation, we might learned what exotic new technologies are only beginning to be used here in the US.