The number of criminal offences by seniors jumped more than 38 percent in one Beijing district from 2008 to 2010, a reflection of the country's fast-growing gray population.

The Beijing Haidian District People's Court settled 18 criminal cases involving suspects aged 60 and above in 2008.

But so far this year the court has handled 25 such cases, said Chen Ming, a judge who compiled the report.

In 2009, the court tried 23 cases involving seniors.

"Many of them were business managers, senior company executives or deputy deans of scientific research institutions," he said.

Chen said nearly half have a high school education and about 26 received a university education.

Most are in their 60s and 70s, and 54 are male.

A majority of the offences were intentional injury, fraud and duty related crimes, Chen said.

Chen said one reason driving the seniors to commit offences was they were near retirement age and, tempted by illegal profit, used their power to commit crime.

In December 2008, 64-year-old Chen Hong, the former female deputy manager of Beijing Ruizhiyisheng Science and Technology Co Ltd, which sells anti-cancer drugs, was convicted of intentional injury and sentenced to one year in jail by the Haidian district court.

The court heard that in order to monopolize the market, Chen assaulted competitors in early 2008 when she was near retirement, causing light injuries to four victims.

Chen Ming said the second reason behind the crimes is that seniors tend to become more emotional due to physiological and psychological changes as they age.

"They are likely to be stubborn, irritable and impulsive. When they become emotional, their language and behavior tend to be offensive," the judge said.

In December 2009, Zhao Yingguan, a 70-year-old retired male worker, was convicted of intentional homicide and was sentenced to 15 years in prison.

In June that year, Zhao got into a minor quarrel with a 68-year-old male he was playing cards with and smashed the man's head with a wooden bench, killing him on the spot.

Chen said the mental setbacks suffered by some elderly people in empty-nest families with children living apart from their parents, or a disintegrated family caused by divorce, or a spouse's death also partly contribute to their committing crimes.

In December 2009, Wang Qiang, a 70-year-old retired male worker from a Beijing petroleum machinery factory, was convicted of intentional injury and sentenced to eight months in jail with a reprieve of one year after he used a luggage cart to hit his ex-wife after a quarrel, breaking her right arm.

Li Guifang, deputy head of the criminal committee of the All China Lawyers Association, said he supports non-custodial punishment for senior convicts, such as probation, community service or fines.

The number of people aged 60 and above in China stood at 167 million in 2009, almost 13 percent of the population, according to the China National Committee on Ageing.