This other thing sounds different to me. They seem to be saying that the agencies are operating in Mexico, not just training. Probably bogus information.
The US has been training native operatives in South America for a long time. A good friend who is a retired police officer, Spanish fluent, trained at the FBI academy then went down south training locals probably 10 years back. They were private contract employees so they got around having military or spies from another country. He told me they were there at the invitation of the government at that time.