Seeking seven more days' custody, police told the court they needed to recreate the crime scene at Lohagad Fort and recover evidence linked to Ketan Agarwal's murder.
Police said both accused deleted their WhatsApp chats, Instagram messages and other phone data. Forensic experts are trying to recover the deleted conversations.
Siya and Ketan were set to tie the knot in November, but she did not want to marry him, prompting her and Chetan to hatch a conspiracy to eliminate him.
Meanwhile, police claimed that during questioning, Siya admitted that fear of social stigma and family embarrassment was one of the reasons behind the alleged conspiracy to kill her fiancé.
Police say Siya Goyal's mobile searches, repeated reconnaissance visits to Lohagad fort and an alleged hand-signal plan helped unravel the murder of Ketan Agarwal.
The father of the deceased alleged that he suspected the girl's family had been aware of the conspiracy from the beginning and might have played a role in it.