Concern is growing in Mexico about an environmental activist and expert on the monarch butterfly who has been missing for more than a week.
Homero Gómez manages a butterfly sanctuary in western Michoacán state, a region which is notorious for its violent criminal gangs.
Rights groups fear illegal loggers may have targeted Mr Gómez for his activism to conserve the local forest which is the home of the monarch butterfly.
He was last seen on 13 January.
Since 2006, 60,000 people have disappeared in Mexico.
Many of them have fallen victim to criminal gangs which control large areas of Mexico and kill anyone who could interfere with their illegal activities, which range from drug and human trafficking to extortion, logging and mining.
Who is Homero Gómez?
Mr Gómez is a 50-year-old agricultural engineer who manages the El Rosario sanctuary for the monarch butterfly, one of the biggest in Mexico.
On his Twitter account he invited people to visit the sanctuary.
En el Santuario El Rosario Ocampo Michoacan “ El más grande del mundo “ pic.twitter.com/WlCJuOcG4Q— Homero gomez g. (@Homerogomez_g) January 12, 2020
He is a tireless campaigner for the conservation of the monarch butterfly. Millions of the species migrate annually from Canada and the US to the conifer forests of Mexico.
The sanctuary Mr Gómez manages opened in November as part of a strategy to stop illegal logging in the area, which is a key habitat for the monarch butterfly. It was praised by the WWF's Mexico director Jorge Rickards as a model of conservation work when it was inaugurated.
What's special about the monarch butterfly?
Scientists have been fascinated with the orange and black butterflies because of the vast distances they fly each year to hibernate in Mexico - the longest migration of any insect.
Researchers found that the butterflies use a kind of internal solar compass to guide them during their flight from Canada and the US to the same area on the border between Michoacán and Mexico state every year.
Once they reach the mountain hillsides of the oyamel fir forests in that area, they cluster together to stay warm. Tens of thousands of butterflies can be seen on a single tree, creating a colourful spectacle which has become a draw for tourists.
But environmentalists have warned that illegal logging poses a major risk for these forests and the butterflies which spend the winters here.
Mr Gómez was last seen in person attending a meeting in the village of El Soldado on the afternoon of 13 January.
Messages promoting his butterfly sanctuary were still being sent from his mobile phone the next morning. But after his mobile went silent on Tuesday afternoon, his family reported him missing.
More than 200 volunteers have joined the search for the environmentalist.
Frustrated with the lack of any clues to his whereabouts, his relatives protested in front of the offices of the Michoacán state attorney general on Friday.
Human rights organisations have also asked the authorities to intensify their efforts to find Mr Gómez and to investigate if his disappearance may be linked to his anti-logging campaign.
Mayte Cardona of the Michoacán Human Rights Commission said that Mr Gómez "was probably hurting the interests of people illegally logging in the area".