A close associate of key accused Bapi Mahato in the May 28 derailment of the Gyaneshwari Express has been arrested from West Midnapore district.
Amiya Mahato was arrested from Koimasoli village last night, Jhargram Superintendent of Police Praveen Tripathi said.
His role in the derailment that led to 148 deaths was yet to be ascertained.
"We came to know that he is a close associate of Bapi, but we cannot say what his role was in the derailment right now," Tripathi said.
Amiya is the seventh person to be arrested in the case, which is being investigated by the CBI.