On the morning of October 30, Gilberto Soto kissed his wife and children goodbye at their home in Cliffside Park, N.J., and drove to Newark Airport to catch a plane for El Salvador.

Soto had been eagerly anticipating the trip because it would be a chance to see his mother in his hometown of Usulutan, visit old friends, and start a new aspect of his job.

At about 6 p.m. Friday, November 5 – the day before his 50th birthday – Soto’s cell phone rang while he was in his mother’s house on a narrow dirt street heavily shaded by trees.

When he stepped outside for better reception, two men with guns ran up and opened fire. He was hit in the back and on the side near the kidney. The latter shot severed his aorta, the major artery to the heart; he was dead before he hit the ground.

The killers ran about 100 yards to a waiting car and sped off. Witnesses said a third man on a bike also got away.

Soto’s friends, family, and colleagues have no doubt that he was killed because of his job: He was a Teamsters Union official leading the campaign to organize port drivers in the Northeast – especially in New York and New Jersey – and in El Salvador, Honduras, and Nicaragua.

Union organizers are not popular in some parts of America, but they are generally not in any grave danger. The same is not true in Central America.

“There was absolutely no attempt to rob Mr. Soto,” says the executive director of the National Labor Committee, Charles Kernaghan, the man who spearheaded the drive against Central American sweatshops, including one used to make a line of clothes for Kathie Lee Gifford.

“It was clear that the sole intent was to kill him,” Mr. Kernaghan wrote in a letter to other labor leaders. “There were several eyewitnesses.”

The murder provoked outrage in the labor movement in America: The Teamsters president, James P. Hoffa, wrote a letter to Secretary of State Powell asking him to pressure El Salvador to conduct a thorough investigation. He also urged other labor leaders to write Mr. Powell.

But the murder has gotten almost no attention in the press in America or El Salvador, just a small Associated Press story about Mr. Hoffa’s letter and a short story in a local paper in El Salvador.

“Union organizers sometimes get arrested here, but murdered, that hasn’t happened in this country in a long, long time,” says the president of Teamsters Local 202 in the Hunts Point Market in the Bronx, Danny Kane, who knew Soto.

“He was a rank-and-filer,” Mr. Kane says. “He started out as a driver down there. We were at a protest together near the U.N. not long ago. He was a terrific guy and an excellent union organizer.”

Gilberto Soto was born in Usulutan, a city best known for being near a volcano, in 1954. He worked as a port driver there for several years before emigrating to America in 1975, where he married, had three children ranging in age from 3 to 22, and became an American citizen.

He joined the Teamsters soon after and eventually became president of Local 11 and a business agent for Local 723. More recently, he was a leading member of the team trying to organize the 50,000 to 60,000 port drivers in America. A tiny handful has been unionized in Southern California, Alaska, and Florida, but wider efforts have failed.

The major shipping lines contend the drivers, who usually own their trucks, are independent contractors and are entitled to union representation. They also contend unionization will just add to their costs and drive up the prices consumers pay for shipped goods.

While most port drivers are unionized in labor-friendly nations in Europe, many Central American countries strongly oppose unions.

In his letter to Mr. Powell, Mr. Hoffa said Soto had a meeting lined up in Central America with port drivers and workers. “I strongly believe that Mr. Soto was assassinated to prevent [this] meeting,” Mr. Hoffa wrote.

Soto’s family here and in El Salvador are calling for an investigation, but their pleas have been met with silence.

Ron Carver, the assistant director of the Teamster’s port division and a longtime friend of Soto, says the union is determined to get the word out about his murder.

“He was an extraordinary person,” Mr. Carver says. “He was still an avid soccer player; a great teacher and mentor. He wasn’t just another union organizer. He was an exceptional guy in a difficult job.”