More than a dozen officers were involved in the response, but Police Commissioner Charles Ramsey said investigators were having the videotape enhanced to help determine how many of them were actually striking the suspects. Police are also relaying their information to the district attorney's office, which will determine if charges are warranted.
"We certainly are concerned about what we saw on the tape," Ramsey said at a news conference. "The behavior that at least was exhibited on the tape is unacceptable."
Ramsey said it was too early to say what kind of discipline the might be warranted. He told CBS' The Early Show that should the district attorney's office throw the case back to the police department, "I'll take appropriate action," adding that he'd judge each officer involved individually.
Police stopped the suspects' car while investigating a triple shooting in the city's Hunting Park neighborhood Monday night. No weapons were found in the car or on the suspects, Ramsey said, but officers said they had witnessed them shoot three people on a drug corner moments earlier.
The video, shot by WTXF-TV from a helicopter, shows three police cars stopping a car on the side of a road. Officers gather around the vehicle and pull three men out. About a half-dozen officers hold two of the men on the ground on the driver's side. Both are kicked repeatedly, while one is seen being punched; one also appears to be struck with a baton.
On the other side of the car,kicking a third man who ends up on the ground.
The three suspects - Dwayne Dyches, Brian Hall and Pete Hopkins, all of Philadelphia - were each charged with attempted murder and related counts in connection with the earlier shooting, police said.
Hopkins' father, Pete, told The Early Show he thinks the officers involved in the beating should be arrested, saying they used "brute force."
"One of them could have been killed," Hopkins said.
The beating happened two days after the fatal shooting of a Philadelphia policeman, the third city officer slain on duty in two years. Ramsey said that officers have been on edge Officer Stephen Liczbinski was slain, but that they still need to maintain a high standard of conduct.
Police are not saying the three men were connected to the police officer's murder, but the killing, the third in two years, weighs heavily on the minds of every Philadelphia cop, CBS News correspondent Randall Pinkston reports.
"There's no excuse for not concucting ourselves properly," Ramsey told CBS News. "There's a lot of stress, a lot of tension."
He added, however that, "The sergeant should have taken some kind of action to intervene."
Liczbinski was shot with an assault rifle after a robbery in the city's Port Richmond section on Saturday. One man was fatally shot by police soon after, another was arrested Sunday and a third was captured late Wednesday.
One expert on the use of police force said the law gives officers broad leeway.
Eugene O'Donnell, a professor of law and police studies at John Jay College of Criminal Justice, said supervisors would likely review the tape to see if there were signs that the suspects were acquiescing even as they were being beaten.
"It is certainly far from unheard of that somebody who was compliant engages in a fatal attack," said O'Donnell, a former prosecutor and police officer in New York. "Until somebody is handcuffed and secured, they could be a threat."
O'Donnell also said that the sheer number of homicides in the city - nearly 400 last year - is enough to put officers on edge.
"If you let your guard down, you can get yourself very seriously hurt," he said. "In the back of your mind, sure it's a city where anybody can get killed. Three days before that, your colleague got killed."
D. Scott Perrine, an attorney for the three suspects, has said that, as terrible as the officer's death was, it does not excuse for what police did to the three men. Dyches suffered a welt on his head the size of a baseball and that one of his legs was seriously injured, Perrine said. He said he didn't know the extent of the other men's injuries.
The mother of one of the suspects said she was outraged.
"I'm horrified to see that our city cops would beat some human being like they did, like a gang-style fight," Leomia Dyches said. "I'd actually like to see them in the criminal justice system. I'd like to see them tried for what they did."