Guwahati, Aug. 4: Police today picked up for interrogation Krishanku Bose, 23, elder son of businessman Koushik Bose, 50, who was killed by unidentified men at his residence on August 2 night at Narikal Basti here.

However, the police clarified that he has not been arrested but detained for questioning.

Koushik died after being hit at the back of his head with a hammer-like instrument. Nearly Rs 30,000, two gold rings and a mobile handset were looted from the house.

The police will also interrogate Maheswar Kalita, caretaker-cum-security guard of RKB Apartment, where the incident took place, and two other persons - Deepak Basumatary and Deven Das - acquaintances in connection with the murder.

Krishanku was the one to inform the police about his father's death after calling the emergency number of Assam police.

The police suspect him to be linked with the incident as a case of jewellery theft is already registered in Geetanagar police station against him, which was filed by his father in October last year.

"In October last year, Koushik filed a complaint against Krishanku alleging that he had stolen all ornaments from the home and sold them. Krishanku was then arrested and sent to jail. He has spent one-and-a-half months in jail and was now out on bail," Geetanagar police station officer-in-charge Chandra Kanta Boro told The Telegraph.

"From preliminary investigation we found that the father and son shared a very bad relationship. So we detained Krishanku this morning. We will interrogate him," Boro said.

On interrogating Kalita, Boro said, "He repeated the same thing which he said yesterday that he did not hear anything at night and does not know if anyone entered the campus or not."

A police source said Krishanku had called Basumatary and Das to inform them about his father's death even before he called the police.

But during interrogation, these two persons did not provide any further information.