A 640-minute period during which murder accused Chetan Chaudhary deliberately remained offline on the day Pune realtor Ketan Agarwal died has emerged as a key breakthrough in the police investigation, with investigators saying the move ultimately helped them trace his alleged role in the murder conspiracy.Siya Goyal, 20, is accused of killing her fiance Ketan Agarwal, a Pune realtor, by pushing him off a cliff during Lohagad trek near Lonavala on June 18 (X and PTI )Siya Goyal, a 20-year-old woman from Maharashtra's Pune, is accused of killing her fiancé Ketan Agarwal, by pushing him off a cliff during a trek to Lohagad Fort near Lonavala on June 18 with the help of Chetan Chaudhary, 22 — allegedly a man who she was in a relationship with.According to police, Chetan switched off the internet connection on his mobile phone at around 7 am on June 18 and remained offline until 5:40 pm, HT earlier reported. Investigators claim he deliberately left his phone at his shop and carried one of his employees' mobile phones to prevent police from tracking his location.However, the strategy backfired. Police said Chetan's nearly 640-minute disappearance from the digital grid itself raised suspicion.Every incoming call to Chetan checkedInvestigators then scrutinised every incoming call made to Chetan's phone during the period. According to police, all callers gave a similar account - although their calls were answered, they never actually spoke to Chetan. Instead, employees working at his shop answered the calls.On Wednesday, police summoned the employee to the police station and began recording his statement.The investigation has also led police to examine the call detail records (CDRs) of accused Siya Goyal and her alleged lover, Chetan Chaudhary. According to Pune Rural Police, the records revealed the extent of communication between the two and helped investigators uncover their alleged secret relationship.A senior police officer involved in the probe said that between January 1 and June 18, Siya and Chetan spoke over the phone 2,004 times. The investigation further revealed that the duo spent a total of 238 hours talking to each other during the nearly six-month period.2,004 calls between Siya, ChetanDinesh Tayade, senior police inspector at Lonavla Rural Police Station and investigation officer in the case, said, "After analysing the CDR data between the two accused, it has come to our notice that there were over 2,004 calls between them, averaging around 8-10 calls per day."The officer also confirmed that calls and messages between Siya and Chetan continued even after Ketan Agarwal's murder. Police are examining the call records among several pieces of evidence as they continue to probe the alleged conspiracy behind the murder.Pune Rural Superintendent of Police Sandeep Singh Gill said, "Yes, we have recovered calls and chats between Siya and her boyfriend, and further analysis of that data is ongoing."Siya and Ketan got engaged in February and were scheduled to marry in November this year. Police suspect Siya was unwilling to proceed with the arranged marriage but could not openly disclose her secret relationship to her family, fearing that breaking off the engagement and eloping with Chetan would disgrace them and tarnish their social standing."Considering societal pressure and her family's image, she did not have the option to elope with Chetan. Hence, she might have decided to find a middle path to ensure she did not marry Ketan while keeping her family's status intact," said an officer familiar with the case.Instead of calling off the engagement, Siya allegedly conspired with Chetan to eliminate her fiancé. Police claim the duo carefully planned and executed Ketan's murder, which was initially presented as an accidental fall during a trek at Lohagad Fort on June 18.Ways to kill searched on phoneSources from Pune Rural Police confirmed that Siya and Chetan allegedly searched for several crime-related methods on their mobile phones. Though Siya was only 20 years old, police claim she was sharp in her planning and allegedly selected Lohagad Fort to execute the plan. According to police, she repeatedly insisted that Ketan visit the fort again and again. Police said she was confident that the murder would not come to light.However, her suspicious behaviour after Ketan's death and during his funeral brought her under the scanner of the Agarwal family.Speaking with HT, Vishal Agarwal, Ketan's father, said, "When the body was recovered and all our family members were in shock, Siya was behaving like a very normal person, which my daughter first noticed."He also claimed that while the family was too distraught to think clearly, Siya was chatting with police officers at the accident scene, asking about next steps and procedures."Maybe she was preparing for the countermove; hence, she was asking about further police action and process," said Agarwal.When HT tried to contact Pravin Goyal, Siya's father, for his reaction, it was learnt that he was hospitalised after feeling uneasy following Siya's arrest.Vishal Agarwal also claimed that Chetan's sister was a close friend of Siya, suggesting Siya's relationship was likely known to the family members.Chetan's family refutes allegationsMeanwhile, Babulal Chaudhary, Chetan Chaudhary's father, refuted the allegations against his son and claimed that he was being framed in the case."Chetan told me that he was staying away from them at the fort. He is being framed by the so-called wealthy people. Siya and Chetan were good friends, and to save herself, she implicated my son," he said.Meanwhile, during custodial interrogation, Siya told police that she was unhappy with her engagement to Ketan Agarwal. According to Pune Rural Police, Siya claimed she informed Ketan she did not wish to continue the relationship and urged him not to proceed with the planned marriage. However, she alleged that Ketan continued to pursue the relationship and remained committed to wedding preparations despite her objections.Police are currently verifying these claims as part of their ongoing investigation into the case.