Homi­cides in New York City plum­meted 22% during the first two months of 2011. But while the record-​​breaking snow that blan­keted the city in Jan­uary seems an obvious expla­na­tion, the New York Police Depart­ment doesn’t have avalanche of evi­dence to sup­port that theory.

Read the article at The Wall Street Journal →