Union minister Kaushal Kishore's son has been booked under the Arms Act, a day after a 30-year-old man was shot dead under mysterious circumstances at his home in Lucknow, police said on Saturday.

The minister's son, Vikas Kishore, was in Delhi at the time when Vinay Srivastava, described as his friend, was shot in the head. The revolver used is a licensed weapon owned by Vikas, according to his father.