The man known as Colombia’s “emerald czar” survived at least two assassination attempts and avoided criminal conviction despite being prosecuted for allegedly forming far-right militias.

What finally claimed the life of Victor Carranza on April 4 was lung cancer. The mustachioed emerald magnate died at 77 at a hospital in Bogota, Colombia’s capital, officials announced.

Mr. Carranza, one of Colombia’s biggest landowners, built his fortune after discovering his first emerald mine as a boy in the late 1940s.

“I’ve been fortunate,” he would say. “The emeralds call me.”

In a 2010 interview with the newspaper El Espectador, Mr. Carranza said he was 2 when his father died. “We were left without protection, five siblings and my mother,” he said. “We had a small farm, and we were very poor. It fell to me to get things going.”

In this March 26, 1996 file photo, Victor Carranza is seen in Colombia. Carranza, a miner who became a billionaire thanks to the exploitation of emeralds, died of cancer April 4, 2013. He was 77. (Miguel Garcia/AP)

A loquacious, gravel-voiced man of humble origins but deep political connections, Mr. Carranza fought three power struggles for control of the emerald sector, beginning in the 1960s. Colombia is known for having the highest-quality emeralds in the world.

The fighting left nearly 5,000 people dead while Mr. Carranza amassed a private army, said the authors of a 2012 biography, leftist Rep. Ivan Cepeda and the Rev. Javier Giraldo, a Jesuit priest.

In the 1990s, Mr. Carranza began to extend his holdings outside the central state of Boyaca where the emerald industry is concentrated, buying properties in the eastern plains around Puerto Lopez.

It was there that he allegedly deepened support for the “paramilitary” militias that are blamed for the lion’s share of killings in Colombia’s decades-old “dirty war.”

In 1998, Mr. Carranza was arrested and charged with kidnapping and forming illegal militias, which prosecutors have blamed for more than 50,000 killings during the past three decades.

Colombia’s chief prosecutor at the time, Alfonso Gomez Mendez, told the Associated Press in an interview that he had no doubt Mr. Carranza was one of the paramilitaries’ principal creators and backers.

Yet after three years in jail, Mr. Carranza, whose attorneys included a former Supreme Court justice, was freed and the charges were dropped.

The following year, Alvaro Uribe was elected president and made peace with the paramilitaries.

Several top paramilitary warlords who surrendered in exchange for reduced sentences identified Mr. Carranza as one of them. One, Ivan Roberto Duque, said Mr. Carranza should not have been called the “emerald czar” but rather “the czar of paramilitarism.”

Cepeda, one of Mr. Carranza’s biographers, said Mr. Carranza was long able to avoid prosecution, because he could rely on “the families that have been governing this country.”

Mr. Carranza was born Oct. 8, 1935, in Guateque, a temperate mountain town about 50 miles northeast of Bogota. Survivors include his wife, Blanca, and five children.

— Associated Press