Concerns for the safety of monarch butterfly defender Homero Gómez lingered Wednesday, more than a week after the Mexican environmentalist went missing.

Gómez, the administrator of the biggest butterfly sanctuary in the western state of Michoacan, El Rosario, disappeared January 13. In a tweet from Jan. 12, Gomez, surrounded by monarchs, encourages people to come visit “this wonder of nature.” His last posts on social media are from January 13.

The lightheartedness of the image belies the threats that came with his work to keep the butterflies’ forest habitat intact.

Mayte Cardona, spokesperson for the Human Rights State Commission of Michoacan, told Reuters, “He was probably hurting the (business) interests of people illegally logging in the area.”