Sleuths investigating the murder of Ajay Agarwal, 19-year-old son of a Burrabazar-based businessman, said on Monday that the youth?s throat had been slit with a kitchen knife, indicating that non-professionals may have committed the crime.

The knife was taken from the kitchen of the Agarwals? Surya Sen Street apartment on Saturday, the day of the murder.

?It appears that the killers were not armed with sharp weapons,? said an officer of the detective department?s homicide wing.

He added: ?However, it is possible that the killers did not want to take the risk of carrying weapons as they knew that they would be able to find knives in the apartment. Generally, professional killers like to use their own weapons.?

Ajay, a Class XII student of an English-medium school in north Calcutta, was found murdered around 7.45 pm by his father Anil. A sum of Rs 1.3 lakh was missing from the apartment.

The investigators have interrogated three friends of Ajay, who were the last people seen to enter the apartment.

?The youths, all of whom studied in the same school as Ajay, have said that they watched television and played computer games in the apartment. They will be interrogated again,? said Gyanwant Singh, deputy commissioner (I), detective department.