Twenty years ago today, Aldrich 'Rick' Ames was charged with spying for the Soviet Union, at least up until the point that it ceased to exist. He'd been arrested the previous day (here's the arrest warrant) after a long investigation which had finally uncovered exactly how Ames and his wife had been able to afford a half-million dollar house on his salary of $60,000 - not to mention a Jaguar for him, tailored clothes, tens of thousands on decor for their home, and a $6,000 phone bill so Ames' wife could keep in touch with her relatives in Colombia.
How had he been doing it? He'd been selling the identities of US agents in Russia to the KGB. For Aldrich Ames was an intelligence officer in the Central Intelligence Agency, and one of the most prolific traitors in the history of the United States.
Amazingly, he'd been at it since 1985, and yet it took until the nineties before he was seriously suspected of blowing the cover of so many agents. He'd been assisted in this by the KGB itself, which leaked a false story that led to extensive investigations into a CIA communications facility in Virginia - which uncovered nothing (apart from the fact that half the people who worked there were unreliable for entirely unconnected reasons). Despite the suspicion falling elsewhere Ames was twice given a polygraph test - but the lie detector detected nothing, partly because he knew how to fool it, and partly because the operator was too trusting.
Ames betrayed his country for money. He had a drinking problem and a new wife to support, and was tired of living on what seemed like a paltry salary. He was paid, in total, about $4.6 million for his espionage ($2m of which was held on account for him in Moscow). And as a result, people died. Secret informants deep within the Russian government started dropping like flies, executed in the traditional Soviet manner: taken into a windowless room and shot in the back of the head, while their remains were buried secretly to deny their families the chance to grieve. Some few survived - Oleg Gordievsky, for instance, was a KGB officer stationed in London who was passing secrets to the Secret Intelligence Service (Mi6), and realised he was in trouble when he was recalled to Russia. With the assistance of SIS, he was able to defect to the UK - barely. Those who had been working at posts within Russia itself rarely had such luck.
Of course, western nations were playing exactly the same game as the Soviet Union when it came to espionage, but there is at least one difference between the two sides: unlike many of those he betrayed, Aldrich Ames was not sentenced to death, but to life imprisonment. He's still there, to this very day.
Here's a short documentary segment on Ames, that begins with what appears to be actual footage of the arrest of one of the people he betrayed (presumably filmed for propaganda purposes, unless it was re-staged later on). Plus there's Ames himself, being (seemingly) honest about what he did.