New York is more violent a city than New Delhi, observes a noted criminologist.

Presenting a comparative picture of gun murders in the two cities before senior officials of the Central Bureau of Investigation in New Delhi on Tuesday, Lawrence Sherman, criminology professor at the University of Pennsylvania, said while there were 400 gun murders in New York in a year, the number was just nearly 35 in New Delhi.

Sherman observed that reducing the gun density in hot spots, particularly in violence-prone areas, will help reduce the crime graph. He also suggested that uniformed patrols be sent to the hot spots for brief visits rather than for longer patrols.

Elaborating on the comparative ratio, he said gun murders in Delhi were just three per million.

The criminology professor put the global trend of crime in three categories -- gun, cyber and domestic violence.

"Sting [Images] operations have proved to be successful in curbing cyber crimes and in cases of domestic violence, while arrests helped only in cases of employed people," he said.

Replying to a query, Sherman said that more research and experiments need to be done to bring crime rate down.

Dispelling doubts about the safety of Indian students studying in United States, the professor stated that freak incidents of violence should not cause anxiety amongst Indian students and their parents.

Professor Sherman has conducted field experiments to find effective ways to reduce homicide, domestic violence, gun violence, robbery, burglary and other crimes in collaboration with different police and prison agencies.