I haven't read the whole thing, but it promises to be informative.
David Wise writing at Reuters:
When the Russian security service in 2011 asked the FBI to check up on Tamerlan Tsarnaev – one of two brothers now suspected in the Boston Marathon bombing – the request would have come as no surprise to a quiet, former FBI special agent in northern California.
Michael di Pretoro had been sent to Moscow in 1994 as the FBI’s first legal attaché, or “legat,” in Russia. He had a daunting task: to establish formal cooperation between the FBI and the Russian police and security services.
The bureau’s hope was that a successful liaison arrangement would help both countries fight Russian organized crime. “There was the issue of loose nukes,” di Pretoro said. “One of my biggest fears was someone would get one of these nuclear weapons and it would cause a catastrophe in the U.S.”
The ex-FBI agent, who now runs his own international consulting business, first persuaded the Russian MVD, which handled criminal investigations, to sign on to the liaison arrangement. Minutes after officially setting up the new office, di Pretoro got a call from the Russian Federal Security Service (FSB) the agency responsible for counterterrorism and counterintelligence.
“We’d like to talk to you about cooperation,” the FSB caller told him. “We think counterterrorism, that’s an area we can work together on.”
Before the year was out, the FBI man had achieved his goal. “We met with the Russians on a regular basis, on nuclear smuggling, organized crime and counterterrorism,” di Pretoro said. “We would have regular meetings with the FSB and the MVD.” The FBI legat met weekly with the Russian police “and once every two or three weeks with the FSB.”
There was a certain irony in the arrangement because the FSB had been developed out of the notorious KGB, the Soviet security and intelligence service. The second chief directorate of the KGB, which had morphed into the FSB, was also responsible for the surveillance of CIA officers working out of the U.S. embassy in Moscow. So the FSB is the agency in charge of counterespionage ‑ of catching American spies in Russia........