NAIROBI, Kenya (AP) — Corrupt Kenyan wildlife rangers are killing poachers to cover up the officers’ collusion with the criminals slaughtering the country’s elephants, a rights group alleges.

The disappearances of 18 suspected poachers were documented by Muslims for Human Rights over the last three years around Kenya’s Tsavo National Park, a huge wildlife sanctuary that hosted 25,000 elephants in the 1970s but which has only 11,000 today.