Aldrich Ames, a CIA officer who became one of America's most damaging double agents, has died aged 84.
The former counterintelligence officer, who was serving a life sentence without the possibility of parole, died on Monday at the Federal Correctional Institution in Cumberland, Maryland, CBS News, the BBC's media partner in the US, reported.
Ames was jailed on 28 April 1994 after he admitted to selling secret information to the Soviet Union and later Russia.
He compromised more than 100 clandestine operations and divulged the identities of more than 30 agents spying for the West - leading to the deaths of at least 10 CIA intelligence assets.
Seeking money to pay debts, Ames said he began providing the KGB with the names of CIA spies in April 1985, receiving an initial payment of $50,000.
Known to the KGB by his code name, Kolokol (The Bell), Ames went on to identify virtually all of the CIA's spies in the Soviet Union, for which he was well rewarded.
To my enduring surprise, the KGB replied that it had set aside for me $2 million in gratitude for the information, he stated in an eight-page document read to the court.
Over the course of nine years, Ames admitted receiving a total of about $2.5 million from the Soviet Union for his betrayal of the US.
The cash fueled a lavish lifestyle, with Ames splurging on a new Jaguar car, foreign holidays, and a $540,000 house, despite never having a salary of more than $70,000 a year.
Ames's 31-year career at the CIA began when his father, an analyst at the CIA, helped him land a job there after dropping out of college in 1962.
He married his first wife, fellow CIA agent Nancy Segebarth, in 1969, before being sent to Turkey as a counterintelligence officer to recruit foreign agents.
Three years later, he was brought back to the US, where his problems with alcohol began to emerge and his marriage began to collapse.
Despite several security violations over the years, including leaving a briefcase full of classified information on a subway, Ames was then sent to Mexico City in 1981.
There he met his second wife, Maria del Rosario Casas Dupuy, a cultural attaché at the Colombian embassy and a CIA asset who would later be charged as his accomplice.
Returning to the US in 1983, Ames became head of the CIA's Soviet counterintelligence department, despite ongoing concerns about his alcohol consumption.
While his career was soaring, his personal life was spiraling. Paying monthly support to his first wife, he also funded Rosario's lifestyle, including her love of shopping.
It was his escalating debts that led him to sell the wealth of secrets that he had access to.
It was about the money, and I don't think he ever really tried to lead anybody to believe it was anything more than that, FBI agent Leslie G Wiser, who was involved in the investigation leading to Ames's arrest, told the BBC.
His treachery began in 1985 when he gave the Soviets the names of KGB officers secretly working for the FBI in exchange for $50,000.
His espionage continued for the next nine years, until his arrest on 21 February 1994, after a mole hunt had begun closing in the year prior.
Ames cooperated with the authorities in exchange for a plea deal that secured a lenient sentence for Rosario, who admitted she had known about the money and his meetings with the Soviets. She was released after five years.
The CIA director at the time, R. James Woolsey, described Ames as a malignant betrayer of his country and noted that the agents Ames betrayed died because a murdering traitor wanted a bigger house and a Jaguar.
