Ghaziabad police have arrested a man for keeping his two sons chained in a small room for the past two months because he thinks they are too mischievous, an official said Sunday.Acting on a tip-off, police in the city's Murad Nagar area raided the home of Shahbuddin and found that two children were chained to a window.Shahbuddin, a rickshaw puller, told police that he kept his sons chained as they were too mischievous and it was the only method to teach them a lesson.The father was arrested for illegal detention, a police officer said, adding that the children will be shifted to a shelter. "We have booked the father for illegally detaining the children," Superintendent of Police (Rural) Jagdish Sharma said.