Four people have been arrested in Kenya as authorities investigate the suspected poisoning of at least 18 elephants near Amboseli National Park.
The Kenya Wildlife Service said three Kenyan nationals and one Tanzanian were detained as part of an inquiry into a series of elephant deaths recorded over the past two months.
Investigators are examining whether the animals were poisoned after eating large quantities of tomatoes treated with illegal pesticides containing cyanide.
Preliminary laboratory tests detected traces of cyanide in crop samples recovered from the stomachs of the dead elephants, officials said.
Many of the animals, mostly adult females and calves, also showed signs of paralysis before dying, which investigators believe could be consistent with cyanide exposure.
The deaths occurred in and around the Kimana area, an important wildlife corridor linking Amboseli National Park with Tsavo National Park in southern Kenya.
The wider Amboseli ecosystem stretches toward the Tanzanian border and is home to more than 2,000 elephants that move across the region in search of food and water.
Farms and human settlements increasingly overlap with elephant migration routes, and crop-raiding is a recurring source of tension between farmers and wildlife.
Authorities are also investigating the possible use of pesticides that are banned in Kenya but are believed to be smuggled across the porous border with Tanzania and used on farms in the Amboseli region.
Environmental officials have long warned that weak enforcement of agrochemical regulations can pose risks not only to people but also to wildlife living close to agricultural areas.
The four suspects have been released on bail while the investigation continues.