NARRATION: Recent scenes have raised questions about the growing militarization of the nations police.

ARCHIVAL (ABC NEWS, 8-14-14):REPORTER: This is not the Middle East. The police in these dark pictures are throwing tear gas at neighbors.

NARRATION: By some estimates, there are more than 60,000 SWAT team raids per year. But it didnt start out that way.

ARCHIVAL (NBC, 12-8-69):ANCHOR: The intermittent warfare between the Black Panthers and police erupted today in Los Angeles. There, a group of them barricaded themselves in their headquarters, and fought police with automatic weapons and hand grenades.

ROLAND FREEMAN (FORMER BLACK PANTHER): When I came out, and I looked up and saw them in their black uniforms and everything. Im like, Hell.Who the hell is this? Black boots, black pants, black shirts. They did not look like police at all.

NARRATION:Thats because Freeman was looking at the very first SWAT team.

The idea was formed in Los Angeles a few years earlier when police were caught off guard by the Watts Riots and had to call in more than 14,000 National Guardsmen.

RON MCCARTHY (LOS ANGELES POLICE DEPARTMENT 1960-1984): The riots in 1965 were a game changera good portion of south Los Angeles was burning to the ground.

PETER KRASKA (CRIMINOLOGIST, EASTERN KENTUCKY UNIVERSITY): They realized they needed well-trained, well-organized people that could handle that level of conflict.

NARRATION: So the LAPD began training a new kind of cop designed to deal with hostage situations and other violent confrontations. Soon, everyone wanted a SWAT team of their own.

RON MCCARTHY: A lot of requests came in to the LAPD SWAT team to go to other parts of the country and train SWAT teams.

NARRATION: As SWAT teams spread across the country, America was also ramping up the war on drugs.

ARCHIVAL (SPEECH, 5-18-88):RONALD REAGAN: When we say no to drugs, itll be clear that we mean absolutely none. No exceptions.

NARRATION: Police were given more authority to enter peoples homes without knocking, to search for drugs, and that increasingly became the job of SWAT teams. In 24 years, the percentage of small cities with SWAT teams grew from 13 to 80. And thanks to surplus military gear, police are becoming more heavily armed.

PETER KRASKA: They dont have to be a particular sized police department. Basically they just need to apply for these things. SWAT had gone from an entity that was all about saving lives in real dire circumstances to prosecuting the drug war inside peoples residences using SWAT teams.

RON MCCARTHY: There has always been in every major city police department, a debate as to is SWAT too militaristic, is SWAT too aggressive?Are those SWAT guys controlled or are they out of control

PETER KRASKA: When the police start thinking in a militaristic way, they start trying to solve their communitys problems in a militaristic way.