On October 20, 1987 three Bhindranwale Tigers Force (BTFK) militants, armed with sten guns shot dead 11 civilians and wounded seven at Chittaranjan Park in South Delhi. The incident occurred just before 2100Hrs. The causalities belonged to the ethnic Bengali community. While the militants were escaping from the scene in a public passenger bus, they engaged in an exchange of fire with Police who boarded the bus to check for the escaping militants. One of them, identified as Subedar Singh was wounded in the leg and later killed by other terrorists, as he slowed them down.

The attack was part of the terrorist tactic to target homogeneous communities to instigate a backlash on Sikhs and flare up communal tensions. Two other militants who were part of the attack were identified as Amritpal Singh and Paramjth Singh, who were later arrested in New Delhi and Punjab respectively. A BTFK militant Surjit Singh Penta was involved in orchestrating the October 20 attack. He was also involved in the Greater Kailash killings in July of same year. Surjit Singh surrendered to Security Forces  in 1988 during Operation Black Thunder-II before committing suicide.