Patna, Sep 15 (IANS) A man in his mid 20s has been arrested on charges of pasting posters threatening Bihar Chief Minister Nitish Kumar, police said Sunday.

Bhimsen Mishra of Maner near Patna was taken into custody late Saturday, Patna's Senior Superintendent of Police Manu Maharaj said.

Maharaj said initial inquiry suggested that the accused was a frustrated man and mentally unsound.

In his posters in Hindi, Mishra vowed to "punish" Nitish Kumar Monday at his weekly 'Janata Darbar'.