LUCKNOW, May 11 -- Days after Chandranath Rath, an aide of West Bengal chief minister Suvendu Adhikari, was shot dead, investigators arrested Ballia native Raj Singh on Sunday night, police said. Singh had earlier contested a local civic election and allegedly maintained links with political figures in Uttar Pradesh.

Senior police officials said Singh, a resident of Anand Nagar locality in Ballia under Sadar Kotwali police station, was arrested in Ayodhya during a multi-state operation carried out by the special investigation team (SIT) of West Bengal Police. He was allegedly intercepted while travelling along the Lucknow-Gorakhpur highway.

Investigators suspect Singh played a role in the logistical planning and coordination of the murd...