A man known as Mexico’s most prominent butterfly activist was found dead in a well, and his family fears he may have been a casualty of cartel violence, according to new reports.

Homero Gómez González, a former logger who became one of the most vocal defenders of central Mexico’s monarch butterfly population, disappeared Jan. 13 — alarming environmental activists throughout the country and the US, the Washington Post reported.

Rights groups immediately suspected that angry loggers or criminal groups in the town of Ocampo in Michoacán state — known for its violent gangs — may have targeted González, according to the report.

His body was found floating Wednesday in a well not far from the El Rosario Monarch Butterfly Preserve he managed.

His cause of death was not immediately known, and his body showed no obvious signs of trauma, authorities told the paper.

But González’s family told local media an organized crime gang had threatened the conservationist, according to the BBC.

His relatives also said they received calls from people claiming to have kidnapped him and demanding ransom, according to the Washington Post.

González was last seen attending a meeting in the village of El Soldado on the afternoon of Jan. 13, and relatives reported his disappearance the next day, the BBC reported.

More than 200 volunteers helped search for González — and entire police forces in Ocampo as well as neighboring Angangueo were detained for questioning last week, according to the report.

González opened his sanctuary in November, an effort to stop illegal logging in the area — a key habitat for monarch butterflies, according to the report.

In a Twitter video published shortly before his disappearance, González is shown surrounded by a cloud of butterflies as he encouraged people to visit the sanctuary.

The Mexican government has outlawed logging in the region, allowing the monarchs to flourish — but the move has fueled tensions between local loggers and conservationists.

“It’s been a fight to maintain it,” González told the Washington Post last month. “And it hasn’t been easy.”