A Cuban security agent known as "Octavio," who for years posed as an independent reporter while spying on dissidents, has died at the age of 83.

The death of Nestor Baguer in Havana was reported by Cuba's state media Tuesday.

The black beret-wearing Baguer's role as an undercover agent was first revealed during the April 2003 trials of 75 dissidents jailed in a government crackdown.

He had been well-trusted until his testimony against writer Raul Rivero and other reporters put the defendants behind bars for terms of up to 28 years.

The Cuban Communist Party newspaper Granma hailed Mr. Baguer on Tuesday, saying that for over 40 years, he fulfilled what it called "the invaluable mission of defending the Cuban people."