Josef Stalin's official biographer suggested Friday the dictator hunted down his hated opponent Leon Trotsky in Mexico and had him murdered by a pickax-wielding assassin.

The implication that Stalin had his archrival assassinated in 1940 was contained in an excerpt of Dmitri Volkogonov's Stalin biography, "Triumph and Tragedy." The excerpt was printed in Friday's edition of the official Communist Party newspaper Pravda.Until Soviet leader Mikhail Gorbachev introduced glasnost or openness policies in 1985, Trotsky was considered an "unperson," never mentioned in the press despite his having been one of the main leaders of the Bolshevik Revolution, second only to Vladimir Lenin, founder of the Soviet state.

But following the revolution of 1917, Volkogonov explains, Stalin outdueled Trotsky in a succession struggle that erupted after the death of Lenin in 1924.

In what was to become one of the most bitter political feuds in history, Stalin eventually had Trotsky expelled from the Communist Party, exiled him to Central Asia and finally had him deported in 1929.

Volkogonov implies that Stalin hounded Trotsky from country to country, and two unsuccessful attempts on his life were made in 1940 in Mexico.

After surviving one of the shooting attempts "the police visited Trotsky and asked him whether Trotsky suspected

nyone in the assassination attempt," Volkogonov writes.

"Of course, Trotsky answered. Leaning toward the ear of the police and not dispensing with his characteristic clowning, he said: Josef Stalin," the biographer says.

Finally in August 1940, a man who had identified himself as Jackson began working as an editorial aide to the exile and entered Trotsky's office with corrected proofs of an article. Trotsky at the time was ironically working on his biography of Stalin, bent over in writing.

"Jackson put his raincoat on a chair, and still unobserved took out an alpenstock and closing his eyes struck Trotsky's head with all his might," Vokoganov writes.

"An awful shriek ensued. Trotsky's agony lasted for a day."

"Yes," says Volkoganov, "Stalin wanted Trotsky dead . . . Trotsky managed to understand Stalin inside and out, his motives and his intentions."

The assassin, whose real name was Ramon Mercader, a Spanish-born communist, was sentenced in 1943 to 20 years for the murder of Trotsky. When released in 1960 after serving 17 years, he came to Moscow to receive a decoration. He eventually died in Cuba.

The murder was never traced to Stalin, but Volkogonov derides the theory that Stalin's police chief Lavrenti Beria organized the assassination without Stalin having ordered it.

Pravda devoted a full page to the excerpts of the biography, written by Volkogonov, who is a general and a military historian commissioned by an official party committee to write the first true biography of Stalin.

Stalin was treated as a god in life, credited with winning World War II and industrializing the Soviet Union during his rule from 1924-1953.

But beginning with Nikita Khrushchev in 1956 and then again under Gorbachev, Stalin has been exposed as a murderer of his own people - killing more than 10 million while collectivizing agriculture and working others to death in labor camps.

Although Trotsky has not been rehabilitated by being reinstated into the Communist Party that he helped bring to power, he can now be written about, and some degree of rehabilitation might even be forthcoming. But Volkogonov sums up the Stalin-Trotsky rivalry in this way:

"Both wanted and strived for being the first. The party dismissed one of them but should have dismissed both."