NAVI MUMBAI, May 28 -- An elderly couple was found brutally murdered in their house in Khalapur tehsil's Nigdoli village by their grandson on Monday evening. An intriguing and sinister component of the crime scene was ash smeared on their faces and all over the house. The victims were identified as Raghunath Dattu Farat, 73, and his wife Surekha Raghunath Farat, 68. Police officials said the murders were likely to have taken place between the night of May 25, when their son last visited, and the evening of May 26, when they were found lying in a pool of blood with their throats slit. A case has been registered against unidentified persons, and an investigation is underway. "Ash was smeared all over the house, not just on the faces of the deceased," said deputy superintendent of police Vishal Nehul. "We are not ruling out any possibility. There are a couple of theories that are being worked upon and we expect the case to be solved soon." According to the FIR lodged by the couple's grandson Aditya Rohidas Farat, his father paid a visit to his elderly parents on Sunday afternoon. On Monday evening, at around 5.30 pm, Aditya, along with his mother and sister, also travelled from Khalapur to Nigdoli to visit his grandparents. On reaching the house at around 5.45 pm, the family found the front door shut. Despite repeatedly calling out to the couple, there was no response. Aditya then proceeded towards the rear of the house. He noticed that a door near the kitchen area was partially open, and entered from there. Inside the house, the youngster found dry leaves, ashes and debris scattered all over the kitchen and bedroom. When he entered the hall, he saw his grandfather lying dead near the door in a pool of blood. Terrified, Aditya rushed out screaming for help, following which his relative, Mayur Ramesh Farat, who lives nearby, came running to the spot. Both of them then entered the house and found deep injuries on Raghunath Farat's neck, seemingly inflicted with a sharp weapon. His face was smeared with ash. The two then went to another room, where they found Surekha Farat lying dead beneath the bed, the floor spattered with blood. She too had injuries on her neck and ashes smeared on her face, the FIR stated. The family subsequently informed other relatives and the police. The police said they were probing the motive behind the killings and examining all possible angles, including robbery and personal enmity. Further investigation is in progress....