On 5 October 1987, 12 Tamil Tigers who were taken into custody by the Sri Lankan Navy committed suicide. They were brought to Sri Lankan Army base in Palali with 5 other unrelated individuals. When Sri Lankan Army attempted to take them to Colombo for interrogation, the 12 committed suicide by swallowing cyanide capsules.
This incident happened two months after the Indian Peace Keeping Force arrived in the northeast of Sri Lanka under the Indo-Sri Lanka Accord.
References
1987 Suicide of Tamil Tigers Wikipedia(Text) CC BY-SA