Patna, Dec. 13: ATM guard Kundan Kumar Malakar's murder has thrown light on the criminals-knowing-victims theory.

Senior superintendent of police Manu Maharaaj said: "We are shocked by the new trend, where criminals have ample time to slit the victim and injure other body parts. Such acts are executed only when the assaulter is known to the victim."

The SSP said in most of the crime incidents, assailants use pistols or revolvers. "The new trend is not only shocking but also reveals the brutality of an incident," the SSP said.

The police have launched the hunt to trace the stolen digital video recorder memory chip, which was attached with the closed-circuit television (CCTV) cameras at the nationalised bank ATM, where Malakar, 45, was hacked to death by criminals in the wee hours of Saturday.

The Patna police on Monday night, led by the SSP and other senior officers, conducted raids.

The SSP's observation assumes importance as prior to Malakar's murder, on November 25, the police had recovered the bodies of two businessmen brothers Abhishek Kumar and Sagar Kumar, who were brutally tortured by assailants before they were killed.

The police arrested Amit Kumar, the youngest of the three brothers.

Amit had hatched the murder plan over a property row.

In November first week, elderly couple Bipin Bihari Sharma and his wife Sunita Devi were strangulated to death in their house at Kidwaipuri.

Police later cracked the case, claiming Bhushan Yadav, a former gardener of the couple, had plotted the dacoity and murder.

City-based psychologist Brinda Singh said: "The trend is dangerous because even a slight provocation can lead to an unfortunate incident. A person with poor upbringing usually has such mentality. People, who have broken families, with frequent clash between father and mother, have such intentions. Such people are psychopaths and have anti-social approach. Social and economical problems are other reasons behind such acts."