As the deaths of 11 family members at a north Delhi home remained shrouded in mystery, mental health experts said today victims in mass suicide cases generally "show commonalities" and suggested that a "psychological autopsy" be conducted in the case to unravel the puzzle. The deceased, including seven women and two children, were found hanging from an iron-mesh in the ceiling yesterday. The incident has baffled investigators and psychiatrists. Police suspect the deaths were part of a suicide pact after handwritten notes found at the house indicated a "religious or spiritual angle". But two members of the family today dismissed the suicide pact theory and insisted the 11 people were killed. A senior doctor from the department of psychiatry at AIIMS suggested that a "psychological autopsy" be conducted in the case to get to the bottom of the mystery. "In layman's term, a psychological autopsy would mean interacting with the victims' relatives, friends and acquaintances to see if there was any pattern - like if they were reading the same book or similar themed books or were part of any cult or were influenced by any occultist," he told PTI on the condition of anonymity. The doctor said the cause of the deaths has not been ascertained yet and therefore a 'suicide pact' remains only a theory at this point of time. Asked what are the factors that drive people to commit suicide en masse, he said: "People who are emotionally very unstable, gullible or vulnerable are prone to enter into suicide pacts". Generally there are several commonalities in such cases, whether of age, religion or some other aspect. "In the Burari case, there is an entire spectrum of age from 15 to 77. And the emotional status of a young person is very different from a middle-aged or old person. Also the number 11 in this case is rather overwhelming for committing such acts," he said. Ten of those dead were found hanging from the iron-mesh, while the body of the 77-year-old Narayan Devi was lying on the floor in a room of the house. The deceased had their mouth taped and faces covered with pieces of cloth cut from a single bed-sheet. Only Devi' face was not covered. Bhawna Barmi, senior clinical psychologist at Fortis Escorts Hospital in Okhla, said: "A common theme in majority of suicidal cults is that they believe in an apocalyptic theology." "Mass or cult suicides occur mostly in groups that feel stuck in their lives and they believe that they are unable to control the consequences of their life. Hence, they often believe that death is the only possible option," she said. This has occurred in a number of cases in the past. Groups of Jews killed themselves or each another to avoid torture, painful execution or being made a slave, Barmi said. Asked what are some of the behaviourial signs these people exhibit before taking an extreme step, she said: "Signs include isolation from any group activity or gathering or avoidance of any social interaction with behavioural changes that can be evident if paid attention to." Other signs include talking about feeling hopeless or having no purpose; talking about feeling trapped or being in unbearable pain; and talking about being a burden to others. "The society around such people should be aware of what is happening around us for our own and other's safety. We should be vigilant and remove the idea of being ignorant just because it is convenient," Barmi said.