Police detained for questioning three people on Thursday, including the owner of an Internet cafe in Kashmir over an email allegedly claiming responsibility for a deadly bombing of the New Delhi High Court, police said.
A powerful bomb hidden in a briefcase outside the High Court killed at least 11 people on Wednesday.
Senior police officers told Reuters said they had detained the owner of an Internet cafe in the Kishtwar region of Kashmir where they suspect the email was sent from early on Wednesday.
Authorities are investigating a claim of responsibility allegedly made in the email by the Harkat-ul-Jihad Islami militant group, an al Qaeda affiliate with bases in Pakistan and Bangladesh. It has claimed responsibility for attacks in India in the past.
Several Islamist group have been fighting against Indian rule of the disputed region of Kashmir.