Seven years ago, more than 200 drug traffickers met on the outskirts of Medellin, Colombia, and formed one of the deadliest combinations for profit of this century, the Medellin Cartel. They supply 80 percent of the cocaine used in the United States. It is smuggled in on a bloody trail of crime and anarchy.

We have tracked the workings of this group and investigated its leaders. From U.S. intelligence officials in Washington, embassy sources in Latin America and highly classified government reports, we have pieced together a history of the cartel.

On Nov. 12, 1981, guerrillas of the revolutionary "April 19 Movement" or M-19, snatched 26-year-old Martha Ochoa from the University of Antioquia in Medellin. M-19 demanded several million dollars in ransom from her family. In polite circles, the Ochoas are known for their collection of fine horses and real estate holdings. Strip away the pretense and they are Colombia's reputed first family of cocaine, presided over by Martha's father, Fabio Ochoa.

Her brother, Jorge Luis Ochoa, reckoned that all wealthy drug traffickers were at the mercy of M-19, which raises money by collecting ransoms. Jorge summoned more than 200 drug traffickers to the family's restaurant. When they left, Jorge Ochoa had formed his own terrorist group with Pablo Escobar, Jose Rodriguez-Gacha, and Gustavo de Jesus Gaviria.

Dozens of people linked to M-19 were killed before Martha Ochoa was released without ransom. The cartel had flexed its muscles and liked the feel. Soon, they were killing competitors in Miami and New York, and assassinating hundreds of police officers, judges and journalists in Colombia.

Pablo Escobar, 39, is believed to be the titular head of the cartel. He has been indicted four times in the United States for drug trafficking but has escaped arrest.

He is believed to have ordered the assassinations of Colombian justice minister Rodrigo Lara Bonilla in April 1984, and American Drug Enforcement Administration informant Barry Seal in February 1984 in Baton Rouge, La.

Jorge Ochoa, 39, and his family transport cocaine to Florida, California and New York. He has been indicted in the United States for drug trafficking and has been arrested twice. The first time was in Madrid in 1984, when he was setting up a European distribution network. He was released on a mere $10,500 bond.

He was arrested in Colombia last November, but was again released. The United States protested and Colombia's Attorney General Carlos Hoyos went to Medellin last January to investigate. Hoyos was murdered. Someone ran his Mercedes Benz off the road and sprayed it with machine-gun fire.

Jose Rodriguez-Gacha, 41, runs his cocaine business out of Bogota and smuggles the drugs through Mexico to Los Angeles. No cream puff, he was accused by the Colombian government of assassinating Jaime Pardo Leal, Colombia's most prominent leftist politician, last year.

Gustavo de Jesus Gaviria, a cousin of Pablo Escobar, has a drug distribution network extending to Florida, Connecticut and Europe. He has been indicted on U.S. charges and uses his drug profits to buy U.S. real estate.