A former employee of Raj Kumar Khaitan was arrested on Wednesday for allegedly murdering the 58-year-old garment trader last week.

Police said Rafique Sardar, in his mid-20s, had stabbed Khaitan to death on the rooftop of a four-storey building in Mott Lane in central Calcutta to “teach him a lesson”. An officer said Sardar had confessed to the crime.

“The accused said Khaitan had sacked him after accusing him of theft last year. Since then Sardar had been plotting to kill the Howrah resident,” said city detective chief Damayanti Sen.

Sardar told the cops that he had taken Rs 32,500, two gold rings and a chain from Khaitan after killing him. “He said all the articles, including the knife he had used to stab the trader, were kept at his Baruipur home. We are yet to recover the items,” Sen said.

“Raj Kumar sacked me last year. I started working in a shop next to his outlet on JL Nehru Road. But he continued calling me a thief. So, I decided to teach him a lesson,” an officer quoted Sardar as saying.

“Sardar had found out that the building had two unmanned entrances. He made a duplicate key of the lock of the door to the roof by taking an impression of the keyhole,” said an officer.

On March 12, Sardar called Khaitan saying he wanted to discuss some matter with him. “Khaitan left his shop around 6.30pm and spent an hour drinking at a club. He then came to Lenin Sarani, from where Sardar took him to the rooftop and killed him,” said the officer.