Jose Angel Martinez, commander of a Mexican border police unit created to aid immigrants, sensed he was in danger after handing his superiors a report alleging high-level government involvement in drug trafficking and immigrant smuggling.

He took his fears to the United Nations top human rights official, who was touring Mexico. He called a local human rights group but got an answering machine. He delivered a copy of his report to a leading newspaper columnist. He confided to everyone he reached that he was terrified for his life.

Within a few days, while making his rounds near Mexico's border with Guatemala on Nov. 29, Martinez was shot through the heart at close range, according to law enforcement and human rights officials.

"His death is a demonstration of the severity of the information contained in that report," said Fabienne Venet, director of Without Borders, a migrant advocacy group, and a longtime Martinez friend. "He told me about some of it in private conversations, but I was out of town when he called. When I heard, I knew he had called to say he feared for his life."

Martinez's death has rallied national and international human rights groups alarmed by what they say has been an increase in attacks and threats against human rights defenders in Mexico at a time when the country is struggling to democratize a government and society ruled for 70 years by the same political party.

"During the past few years a campaign to harass and persecute has been waged against human rights defenders," was the assessment of All Rights for All, a national network of 48 Mexican advocacy groups, in a recent report that cited 113 incidents. "This campaign includes death threats, surveillance, fabrication of crimes, intimidation and theft of information and equipment."

U.N. High Commissioner for Human Rights Mary Robinson, who visited some of Mexico's most troubled states last month, said the protection of human rights activists, as well as others whose work involves rights issues, is a major focus of her agenda here.

In response to the growing criticism, the Foreign Ministry said in a statement this month that "the government of Mexico considers unacceptable all acts that violate the integrity of people dedicated to the cause of human rights in our country." Government officials referred reporters to the statement when asked to comment for this article.

Although no organization has compiled a comprehensive list of activists, journalists and local politicians who have been killed, arrested or threatened as a result of their rights work, human rights groups documented scores of cases this year.

Those incidents included an assault on a lawyer for the prominent Miguel Agustin Pro Juarez Human Rights Center in Mexico City. She was tortured and tied to a chair in her house on Oct. 28 and interrogated for eight hours about her cases, including one in which she defended two environmental activists allegedly tortured by the Mexican army during detention in the Pacific Coast state of Guerrero.

The documented cases also included the killing of an activist who had opposed a Boise Cascade Corp. logging project in Guerrero; death threats received by a Roman Catholic priest in the southern state of Oaxaca in April after he intervened in election-related rights cases; and threats directed at activists in the northern industrial city of Monterrey who tried to improve prison conditions.

To human rights advocates, no case better illustrates the dangers of fighting the system than the killing of Martinez, commander of the Beta Group, one of several Mexican police units charged with protecting the rights of migrants along Mexico's borders.

Martinez, whom one human rights official described as "profoundly honest," had compiled a report describing the involvement of senior government officials, prominent industrial leaders and federal police in the illegal trafficking of drugs, migrants and weapons in Tabasco and Chiapas states. Among those implicated were family members of a former Tabasco governor.

Three days before he died, Martinez telephoned Jorge Fernandez Menendez, a prominent columnist for the daily Mexico City newspaper El Financero "to tell me . . . that he was under a lot of pressure and that corruption was overflowing because that border area had become one of the major routes for drug and alien trafficking," Fernandez wrote.

Martinez gave the columnist a copy of his report, details of which Fernandez published after Martinez was killed.

Authorities have charged Anacarsis Peralta, a colleague of Martinez, with murder. Miguel Rodriquez, Peralta's attorney, said Peralta told police that the shooting was accidental and that he tried to get Martinez to a hospital after the gun went off.

Jorge Canel, administrative coordinator of the National Migration Institute in Tabasco, said some agency officials believe "somebody paid [the killer] to be the trigger man."

In addition to physical violence and threats, human rights organizations increasingly are verbally assaulted by politicians, business leaders and church officials. Rights workers were stunned earlier this year when Cardinal Juan Sandoval in the central state of Jalisco launched a tirade against the state human rights commission for "constantly defending delinquents."

The cardinal added: "Human rights are not in question. Rather, in question, is this human rights organization whose work has not been beneficial to society."

"As crime gets worse, people legitimately want some state response," said Joel Solomon, Americas research director for Human Rights Watch, an international monitoring organization. "Human rights groups are seen as a straitjacket in the fight against crime. It's a lot easier to blame human rights procedures than it is to resolve the fundamental problem."

National and international human rights organizations praise Mexico for signing several global conventions on human rights in recent years and establishing a national human rights commission to investigate offenses. But the organizations criticize the commission and the government for their failure to adequately investigate and prosecute offenders.

"Mexico considers it important to develop a culture of human rights at all levels [and] to strengthen institutions charged with bringing justice and stopping impunity," said the Foreign Ministry.

Researcher Garance Burke contributed to this report.

CAPTION: The killing of Jose Angel Martinez, a police commander who wrote a report about official corruption, galvanized human rights groups.