Strangulation marks were detected on the neck of popular TV actress Pratyusha Banerjee, indicating death due to asphyxiation and hanging, according to a preliminary autopsy on Saturday evening.The "Balika Vadhu" actress was found hanging from a fan in her residence on Friday evening and died in hospital later.A team of doctors conducted the post-mortem for over three hours and the entire procedure has been videographed. The viscera samples have been sent for forensic analysis even as the final autopsy report is expected later.Though officials declined to comment, a tattoo bearing the name 'Rahul' - purportedly referring to her boyfriend, Rahul Raj Singh - was found on her upper back.Her last rites were subsequently held.