CHENNAI: A red suitcase sitting unclaimed in the general compartment of the Tamil Nadu Express set off a chain of discovery that would eventually unravel a chilling murder plot stretching from a rented house in Chennai’s outskirts to a railway station nearly 2,000 kilometres away in Agra.Inside were the dismembered remains of a 38-year-old pregnant woman, allegedly murdered by her lover after she refused to terminate her pregnancy and repeatedly pressured him to marry her, police said.The victim, Hayathun Nisha, a native of Odisha, had been living at a rented house on Mosque Street in Guduvanchery, where she was murdered earlier this month, police said. Investigators suspect that after killing her, the accused shaved her head and smashed it to make identification difficult, before packing her dismembered remains into the suitcase and sending it aboard the Tamil Nadu Express.The train had left Chennai Central for New Delhi on August 3. Two days later, on August 5, railway police checking an unclaimed suitcase at Agra Cantonment railway station made the gruesome discovery, bringing the case to light.Since the train had originated in Chennai, investigators turned to CCTV footage from Chennai Central and other stations along the route. The footage showed a man and a woman carrying the suitcase, a lead that helped police trace their movements back to Guduvanchery.Piecing together CCTV footage, mobile phone data and other technical evidence, Guduvanchery police tracked down the accused — Manik Uddin Laskar, 22, from Assam, and his wife Bhagabati Majhi, from Odisha — all the way to Kashimpur in Manipur’s Jiribam district on Saturday. The couple was arrested and brought back to Guduvanchery on Sunday for further investigation.The trail led investigators to the rented house on Mosque Street where Nisha had been staying, where more body parts were recovered from a large cooking vessel, police said.As the investigation progressed, police began probing Nisha’s relationship with Manik Uddin and discovered she had become pregnant. She had refused to terminate the pregnancy and had been insisting that Manik marry her, which police said led to frequent arguments between the two.It was this escalating conflict, investigators suspect, that pushed Manik and his wife to a chilling decision — to kill Nisha. After the murder, they allegedly dismembered her body, packed some of the remains into the suitcase, and carried it to Chennai Central before placing it aboard the Tamil Nadu Express, investigators said.During interrogation, the couple allegedly revealed a particularly gruesome detail: Nisha’s head had been shaved after it was severed. They had initially tried to fit it inside the suitcase but could not, following which they allegedly smashed it into smaller pieces to pack it in, police said.Investigators believe the mutilation and shaving of the head were deliberate attempts to make it harder to identify the victim.Police are now coordinating with Agra railway police to trace the remaining body parts and determine whether all the remains transported on the train have been recovered.