Tinsukia/Sivasagar: The co-accused in Assam's twin train murder case, Bipin Pandey, was arrested from S-2 coach of Dibrugarh-Bangalore Express at Banipur station in Dibrugarh town in the wee hours on Friday.

Additional superintendent of Dibrugarh police Surjeet Singh Panesar said, "Bipin's mobile was put under surveillance, which gave a crucial lead that he had boarded the Dibrugarh-bound Bengaluru Express at Dimapur railway station."

"The entire force was alerted. A joint team of GRPF, RPF and Assam police was deployed at various stations and a close watch was kept. At Simaluguri, the train was detained and a thorough search was conducted but somehow he evaded the eyes of security forces. From Simaluguri, the train moved ahead without any halt or slowdown in between, except regular stops where forces were already in place," he added.

"Over a hundred jawans had been deployed at Banipur station, including along railway tracks, to ensure that he did not jump from the train when it slows down before entering the station. A thorough search was conducted and he was arrested from S2 coach at 2.30am," Panesar said.

"During interrogation, Bipin confessed to have raped and murdered the two victims with Bikash Das, the prime accused, on Tuesday and Wednesday. They raped them again after killing," he added.

Bipin also confessed to have raped and murdered a woman on Avadh-Assam Express in August last year, Panesar said. The body was recovered from the toilet of the train at Banipur station.

Bipin's mobile phone and other belongings have been seized and he was handed over to the GRPF, Simalguri, Panesar added.

Bikash was picked up from Tinsukia railway station on Thursday and later arrested.

Senior divisional security commandant of Tinsukia railway division, Bharat Singh Meena, said Bikash had returned to New Tinsukia railway station after committing the crime on Tuesday. He slept the night on the platform before leaving for Dibrugarh in DEMU train. There he met Pandey and they both boarded the Avadh-Assam Express and again committed a crime on Wednesday.

Meena said Bikash told interrogators that both the victims murdered recently had pleaded for their lives.

The two accused were interrogated at Sivasagar police station on Friday.

Sivasagar additional superintendent of police Bolin Deuri said, "We will bring Tara Devi, mother of Radha Kumari, who was murdered by the duo on Tuesday, to the police station to identify if Bipin was the person she saw in the coach when she went to see her daughter off at Sivasagar railway station."

The police produced Bikash at the sub-divisional judicial magistrate court in Nazira, 15km from Sivasagar, and sought his remand for 14 days. Bipin will be produced before the court on Saturday, Deuri said.

The police found traces of semen on Pandey's trousers and sent it for forensic examination, Deuri added. Meena said Bikash's undergarments, which he had not changed since rape and murders, were also sent for forensic examination.