Mexico City, Jul 1 (IANS/EFE): 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," said the investigative reporter and women's rights activist, who has exposed prostitution and child-pornography rings.

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".