Calcutta, June 13: Calcutta police met some of Partho De's relatives at their Gurusaday Dutt Road residence today and were told that he had called them up several times in the past few months asking about one of his cousins, sources said.

The police visited one of the four siblings of Partho's mother Arati, hoping to get details that would help them understand the De family better.

"His (Partho's) aunt told us that in the past few months, he had called up her family again and again, mostly seeking specific details about one of his cousins. Partho's aunt has two daughters, both of whom are settled abroad. She said he asked questions about one of them," an officer said.

According to the police, the family stopped taking his calls, disturbed by their frequency and the nature of queries.

"It could be that after the death of his elder sister, whom he loved dearly, he had started looking for the same kind of affection from one of his cousins. However, doctors would be able to explain his behaviour better," a Lalbazar officer said.

Investigators said that in the absence of anyone who could shed light on the cause of Partho's elder sister Debjani's death, the police were taking everything into account, even the statements of his distant kin.

The police have learnt that Partho's aunt and her family had lost touch with the Des after the death of Arati in 2005. "They were not in touch for long. Recently, Partho started calling them up," an officer said.

The police today got a court's permission to question Partho at Calcutta Pavlov Hospital.

References made in Partho's diary, which is in the possession of the police, have suggested a complex relationship between the siblings and the father and daughter.

"Everything is interrelated. We would like to ask Partho a few things without agitating him or disturbing his state of mind. The questioning would be done in the presence of a psychiatrist," an officer said.

Sources said the police would carry Partho's diary during the questioning and ask him about the paragraphs where he had mentioned his sister, mother and father.

"There are places where he seems to have juxtaposed parts of a novel with real life situations. We need to clarify that. We would have to dig deep since it may hold the key to Debjani's death and (Partho's father) Arabindo's decision to end his life," an officer said.