Mexican journalist and author Lydia Cacho told authorities she has received death threats for revealing the names of sex traffickers and urged them to take action to identify the perpetrators.

"Last week, as I was returning from an event in (the northern state of) Chihuahua, I received very specific death threats," Cacho said in a statement released Wednesday, adding that after investigating the source of the threats she decided to report them to authorities.

"We have clear signs of who these people claiming to be hit men are. There's also evidence of the origin of the calls and e-mails. Authorities have the responsibility to act," the investigative reporter and women's rights activist, who has exposed prostitution and child-pornography rings, said.

She recalled that several journalists have been killed "after receiving very similar threats," although they were disregarded at the time by the authorities and the recipients themselves.

The idea was that "those who threaten don't kill, but that's changed," Cacho said.

She said experts who analyzed the threats she received last week and the format in which they were sent urged her to "take them very seriously and take all appropriate precautions."

The journalist and author said she is not asking for any special treatment but only wants authorities to do their duty to investigate "those who are promising to torture me and end my life out of revenge for revealing the names of traffickers of girls and women."

"I don't have the slightest intention of ceasing to practice journalism and work in defense of human rights, but I also don't want to die or risk my life without (taking) necessary precautions," Cacho said.

The journalist has been the target of threats since 2005, when she published a book, "Los demonios del Eden" (The Demons of Eden), that exposed pedophile rings operating under the protection of politicians and business leaders.

For publishing the crimes of Lebanese-born Mexican businessman Jean Succar Kuri and others, Cacho was the victim of kidnapping, torture and police abuses, which she revealed in another book titled "Memorias de una infamia" (Memoirs of an Infamy).

In it, she detailed her arrest in late 2005 in Cancun on charges of defamation - a criminal offense in Mexico - filed by Kamel Nacif, one of Mexico's richest men, whom she had identified as a friend and protector of Succar Kuri.

She told of being taken to Puebla, a city more than 1,000 kilometers (620 miles) away, and of being psychologically tortured and threatened with death.

In early 2006, Mexican newspapers published transcripts of wiretapped conversations between Nacif and the then-governor of the central state of Puebla, Mario Marin, in which the two men discussed a plot to have Cacho jailed and then sexually assaulted behind bars.

On the tapes, Nacif, known as the "denim king" for his dominance of the blue-jeans business, is heard telling Marin that he had arranged for "the crazies and the tortilleras (Mexican slang for lesbians)" to sexually assault Cacho in the women's prison in Puebla city.

The transcripts indicate that Nacif engineered the journalist's arrest by bribing court personnel not to send her the summonses for the defamation case.

The reporter's lawyers managed to get her out of jail before any harm could come to her and the defamation case against her was later dismissed.

In her weekly newspaper column and other published works, Cacho also has revealed precise information about people trafficking, organized crime, drug trafficking, gender-related violence and official corruption.

The author's most recent book, "Esclavas del poder, un viaje al corazon de la trata de mujeres y niñas en el mundo" (Slaves of Power: A Journey to the Heart of the World Sex Trafficking of Women and Girls), exposes global sex-trafficking rings and reveals the names of public officals who protect them.