Arrested top Lashkar-e-Taiba terrorist Abdul Karim Tunda, an expert in making destructive improvised explosive devices, has been the involved in terror strikes over the past 20 years. Police say some of his most active phases are:
* March-December 1993: Mumbai serial bombings March 12 left over 250 dead.
Between Dec 5-6, he also carried out seven blasts in trains in Hyderabad, Gulbarga in Karnataka, Surat in Gujarat and Lucknow in Uttar Pradesh.
* December 1996-98: Blasts in New Delhi, Panipat and Sonipat in Haryana, Ludhiana in Punjab and Kanpur and Varansi in Uttar Pradesh.
One of the most devastating explosion was in a crowded private bus at Punjabi Bagh Dec 30, 1997 in west Delhi killing four commuters.
* October 2010: Police say Tunda tried to cause serial explosions in India in 2010, ahead of the Commonwealth Games in Delhi, using human traffickers active in Bangladesh.