Deadheads level 6

An English rose garden on a summer´s day. A small boy watches with interest as his great aunt cuts the deadheads off the rosebushes with a sharp knife. What could be more peaceful, more harmless? Young Patrick grows up to be a calm, pleasant man, with a good job, a wife and two children, and the best rose garden for miles around. When somebody tells the police that Patrick Aldermann is killing people, Chief Superintendent Dalziel thinks it´s probably all nonsense..