Another view of the Boston bombing
I'm reminded of the capture of the "Beltway Snipers." The police were searching for a white van (which wasn't their vehicle at all) and a lone disgruntled white guy (which is what the profilers said). The leader of the two called the special hotline and told them he was the sniper and wanted money. They thought he was a crank and kept hanging up on him. He called 911, and was told all sniper calls must go to the special hotline only. He finally called a clergyman, convinced him, and the clergyman got through.
Then he directed the money to be wired to an account which was easily traced to him. From there they got his vehicle and plate number.
But they decided to keep it secret, so as not to tip him off. But then they broadcast the data on unencrypted radios, so the media got it and broadcast it.
A trucker at a roadside stop heard it, spotted the car, called police and blocked it in. Then they finally caught the killers.