Overkill: The Rise of Paramilitary Police Raids in America

http://www.cato.org/pub_display.php?pub_id=6476

http://www.cato.org/pubs/wtpapers/balko_whitepaper_2006.pdf

These increasingly frequent raids, 40,000 per year by one estimate, are needlessly subjecting nonviolent drug offenders, bystanders, and wrongly targeted civilians to the terror of having their homes invaded while they're sleeping, usually by teams of heavily armed paramilitary units dressed not as police officers but as soldiers. These raids bring unnecessary violence and provocation to nonviolent drug offenders, many of whom were guilty of only misdemeanors. The raids terrorize innocents when police mistakenly target the wrong residence. And they have resulted in dozens of needless deaths and injuries, not only of drug offenders, but also of police officers, children, bystanders, and innocent suspects.

Also see this map:
http://www.cato.org/raidmap/