THE murder of a 52-year-old American in a Delhi Hotel would not have merited a comment had it not been one of a disturbing series of stories that have appeared in recent months about attacks on and murders of foreign tourists in India. The number of such crimes is still small, but like water dripping into a bucket, they are beginning to form a pool that is changing foreigners' perception of India as an exceptionally safe place. This is happening not so much because of the crimes as the reluctance of the police to carry out a proper investigation.