|Jagtar Singh Hawara (l) along with his associates Vikas Sehgal and Jaspal Singh|
The explosions killed one person and wounded 49 others.
Police say all three detainees belong to the Sikh militant group Babbar Khalsa. Jagtar Singh Hawara is a senior leader who heads the group's operations in New Delhi. He was involved in the assassination of Punjab Chief Minister Beant Singh and had escaped from jail in January 2004.
Police say they are still looking for a motive and the source of the money used for the attacks.
Two other activists were arrested in the capital last month in connection with the bombings.
Some information for this report provided by AFP.