On 15 October 1987, two companies of Central Reserve Police Force were ordered to move to Karawadi East (Tropo area) in three vehicles from Palali Airfield in Sri Lanka as part of the Indian Peace-Keeping Force (IPKF) operation. On the way, the convoy was ambushed by the militants with RLS, mortars and automatic weapons. The personnel sitting in the body of the vehicles promptly returned fire with LMG, while the vehicles kept moving ahead. Constable Thankappan Mohan was hit by bullets in the chest, and his shoulder was badly lacerated. With indomitable courage, he continued to man the LMG, bringing down heavy fire on the militants till he finally collapsed and died. By his sacrifice he saved the lives of his comrades-in-arms.

Constable Thankappan Mohan displayed conspicuous courage and valour in the face of the militants.