Fortunately for police and the public, news is immediate, and the public does not have to wait 24 hours to hear it in traditional mass communication. Twitter is an efficient way to spread the news to the public. With new budget cuts on the rise, twitter offers police departments a cheap alternative to other forms of police reports.
On the contrary, Twitter as a form of news can be a bad thing. Twitter is limited to 140 characters, so the police are somewhat limited in what they can say. While they could post multiple tweets, it is hard to know, how many is too many? Police do not want to bombard the public with news, as it may lessen or worsen the severity of an issue. There is also the concern that the public might flock to a crime scene once a tweet is posted.
All in all, I think that police departments should use tweets with limitations. They should not rely on tweets but also report news in traditional media. It is great that organizations like police departments are embracing new technology and ideas.