Two park rangers were among the seven persons detained Monday on allegations that they were growing marijuana in Parque National la Amistad.
The two park rangers are employees of the Ministerio de Ambiente y Energía.
The arrests came during a series of eight raids in Pérez Zeledón and Buenos Aires. Three woman were among those detained.
The allegation is that the marijuana was cultivated in a section of the park near Pittier de Coto Brus. The park straddles the Costa Rica-Panamá border, and it is fairly remote.
Judicial investigators said that the marijuana was distributed as far north of the Central Valley. They said that seven other persons had been detained earlier and said that these were members of the same organization.