Three teens were handcuffed after US Park Police say they sold bottled water illegally on the National Mall.
It happened Thursday shortly after 5 p.m.
Tim Krepp, a former Naval Officer and father of two, snapped photos of what he saw and tweeted them.
"It's was a humiliating posture rather by intent or neglect. They were humiliating these teens," he said. "They could of done other actions not handcuffed them and left them on the ground."
US Park Police said the undercover officers were doing their job. The teens were allegedly vending in a prohibited area which is illegal.
US Park Police said, during an investigation, it's not uncommon for officers to handcuff people for the officer's safety.
Krepp said police went too far.
"It's not uncommon for this to happen and that is the problem. This is typical and they don't see this as a problem," he said. "I walk by these same black youths selling water each day I don't feel unsafe walking by them certainly the guy with the badge and the gun could feel a modicum of safety as well."
In 24 hours, Krepp's tweet has been retweeted and liked tens of thousands of time.
"The viral phenomena is good. It made some noise," Krepp said. "The idea that we can do these things in quiet, it's all too prevalent, so a little noise, a little discussion, is good. It's a messy conversation. No one is wrong or right and we are not going to solve it by keeping quiet," he said.
Park police said the teens were given a verbal warning for illegal vending in a prohibited area. They were released to their guardians.