Patna, Nov 23 (IANS) Death toll in the Patna serial blasts rose to seven after an injured man died in Bihar's Nalanda district, police said Saturday.

Lakhan Rajvanshi, a resident of Nalanda district's Pandiptpur area, critically injured in the Patna serial blasts, died Thursday, a police officer said.

After initial treatment in Patna, Rajvanshi had returned to his village and was being treated at a local hospital, the family members said.

At least six people were killed and nearly 100 injured in the serial blasts in Patna ahead of a rally addressed by the Bharatiya Janata Party's prime ministerial candidate Narendra Modi.

Besides, a suspected bomber was also killed.

The NIA has arrested four people including Mohammed Imtiyaz Ansari in connection with serial blasts in Patna.

The NIA is probing into the serial blasts.