After murdering three of his family members followed by taking his own life in Gurugram's upscale Uppal Southend on Monday, Dr Prakash Singh (55) tried to destroy evidence by putting three mobile phones into the water bucket to erase their memories, police said on Tuesday.Aman Yadav, Assistant commissioner of Police of Sadar zone, said the mobile phones have been recovered and technical experts are on the job trying to retrieve the data."We have received call details of all the four deceased. We are waiting for reports from our cyber cell and are also scanning their emails to corroborate the reason for the deaths," Yadav said.Prakash allegedly killed his wife Sonu Singh (50), daughter Aditi (22) and son Aditya (13) using sharp weapons and a hammer on Sunday night inside the bedroom of their flat. The accused allegedly stayed for some time with four pet dogs and gave them food. He allegedly committed suicide by hanging himself from the ceiling fan in the drawing room."Prakash, after committed the crime, had also washed his hands in the basin. Finger print experts have found the impressions," said Subhash Bokan PRO of Gurugram police.The Gurugram police conducted the post-mortem of the four persons and handed the bodies to the families.A relative of the family said Prakash was paying EMIs of home loan since he purchased his house some 8 years ago. He had also borrowed some money from relatives and friends.A top official said the deceased's daughter Aditi had shared domestic problems, including her father's depression, with her close friends."Since the matter is sensitive, we have taken statements of every person linked to the family," an official said requesting anonymity.Prakash, a gold medallist from Banaras Hindu University (BHU), had a love marriage with Sonu Singh who is also a gold medallist. She ran a pre-school nursery in Gurugram.