MUNICH — The images showing a wall of armed, helmet-wearing men in camouflage uniforms look like something from a war zone. A sharpshooter sits on an armored vehicle, gun at the ready, looking through the rifle scope as if he were about to fire.

But the photos weren't taken in Afghanistan or Iraq, although comparisons of images taken in both places have an uncanny similarity. They were taken in Ferguson, the small Missouri town that, for all the wrong reasons, the world is watching. The men aren't American soldiers, but officers for the local police force.

Since last Saturday's police killing of 18-year-old black teen Michael Brown, who was unarmed and repeatedly shot, there have been daily demonstrations in Ferguson. People have lost faith in the police, who in turn feel threatened and are arming up. Heavily armed police have unleashed tear gas and rubber bullets on peaceful protesters.

While the scenes playing out there are disturbing, they are actually the manifestation of a trend that has been building for years in the United States. Since 9/11 and the fight against terror that it engendered, American police have become increasingly militarized, both in terms of their training and their equipment.

Rise of the Warrior Cop, a book byAmerican journalist Radley Balko, tackles this very subject. In a Wall Street Journal essay, he estimates that between 2002 and 2011 the Department of Homeland Security (DHS) distributed $35 billion of equipment to federal police and local police stations.

Add to that the support of the Pentagon. The police in Ferguson are part of Program 1033, through which military equipment can be acquired. And not just protective gear or small arms, either. The list of available items includes heavily armored vehicles of the sort used in Afghanistan and Iraq, but also assault weapons. In 2013 alone, the program distributed equipment worth $500 million to the police.

That fuels some bizarre situations. The city of Fargo, North Dakota, where there are fewer than two murders per year, owns an armored vehicle with a gun turret. In Keene, New Hampshire, $286,000 was spent on a BearCat armored vehicle. Between 1999 and 2012, there were three homicides in Keene. The local police chief said that the BearCat was mainly for use at major events — such as the Pumpkin Festival.

Meanwhile, many police stations not only have heavy weaponry but also SWAT teams. These special forces originally were to be used in life-threatening operations such as shootings or hostage-takings. In the mid-1980s, 80% of towns with populations of 50,000 inhabitants had SWAT teams, but by 2007 over 80% of towns with populations between 25,000 and 50,000 had such a team.

In 1980 SWAT teams across the United States were called in for 3,000 operations. That has since become 50,000, as researcher Peter Kraska tells The Economist. They are dispatched to make arrests or break up illegal poker games. In 2010, a SWAT team burst into a bar that was supposedly serving alcohol to minors. The special has become routine. SWAT teams have also been called in during the Ferguson protests.

Balko writes that operations involving the heavily armed SWAT teams often end with bloodshed. He himself has counted 50 cases in which innocent people died. Some of these people were bystanders, some were police that suspects thought were burglars.

Of the current situation in Ferguson, Balko says, "The police no longer see people as citizens with rights. They see them as a threat."