Story highlights A video captures Connor Castellani yelling and gesturing at officers outside a casino

Then Atlantic City officers tackle him, hit him with clubs, according to the video

A police dog bites at the man's neck and drags him to the curb, according to the video

The man is suing, the police chief says he is "absolutely" standing by his officers

The visible wounds on David Connor Castellani's head and neck are healing, but the scars remain from the night he was arrested and beaten by five Atlantic City Police officers and bitten by a police dog in an incident captured on video.

In an exclusive interview with CNN's Jason Carroll, Castellani, 20, said he has total numbness on the right side of his head, and severe nerve damage. "It's definitely the worst thing that's ever happened to me in my life," the Temple University junior said.

Castellani and his parents have filed a lawsuit in federal court against Atlantic City and its police department.

The arrest and beating was captured on surveillance video in the early morning hours of June 15, after Castellani was told to leave the Tropicana Casino and Resort because, he said, he is under 21.

The video shows Castellani yelling and gesturing at the officers who are not visible on the video at that time. Several officers tackle him and start hitting him with clubs and kneeing him, according to the video.

After officers wrestle with and hit Castellani for almost full minute, the video shows a K-9 van arriving. An officer gets out and releases a police dog onto Castellani, who by then was flat on the ground surrounded by five police officers still seemingly attempting to handcuff him, the video shows.

The video shows the police dog biting at Castellani's neck and dragging him to the curb, before the scene becomes obscured by the police van.

Castellani told CNN that during the incident "I was just basically rolling up in a ball -- I wasn't resisting, I told them that, and they continued to beat me. I was holding on for life when the dog bit me."

Atlantic City Police Chief Ernest Jubilee told Carroll that an internal investigation of the incident is underway, but he is "absolutely" standing by his officers.

"I stand by the officers. I stand by their actions. If the investigation bears something different, then we'll deal with it at that time," Jubilee said. The officers involved all remain on active duty.

Castellani's parents told CNN they were horrified by what they saw on the video. "I was just numb, went home and got sick." Theresa Castellani said. "You don't want to see that happen to anyone, but especially your own child...that was horrible."

David and Theresa Castellani and their son filed a civil lawsuit this week in U.S. District Court in Camden, New Jersey.

They say they are hoping to change the Atlantic City department's policies and procedures, and they also are seeking monetary damages. They also ask that the police involved be prohibited from serving as law enforcement officers.

"I think it's really the sum total of the (police) administration allowing these officers to perpetrate this kind of conduct and to continue to allow them and empower them with this abuse of authority," David Castellani said. "They're there to help you, not to hurt you. To see this kind of conduct, a beat down on my son and then the use of (a police dog) on his neck ... it was shocking beyond belief."

When CNN Law Enforcement Analyst Lou Palumbo reviewed the entire surveillance video, however, he said he believed the amount of force used by officers was appropriate.

Palumbo, a former law enforcement officer, said Castellani seemed to have precipitated the confrontation with police by verbally taunting them, even after they initially were willing to let him walk away.

"This is the problem you have. If the police order you and want to place you under arrest ... you ought to comply," Palumbo said. "All they wanted to do was get this kid under control and handcuff him."

Palumbo acknowledged that the release of the dog was "a gray area," noting that "perceptively it's terrible," but pointing out that Castellani was still not handcuffed at the time and that "dogs are used for compliance."

But 20-year police veteran Jon Shane, a retired police captain who now teaches police practice at John Jay College of Criminal Justice, was critical of all officers shown on the video. He said it's unclear to him how Castellani's behavior, as shown on the video before police tackle him, even rises to the level of disorderly conduct.

"I don't see any fighting, threatening or tumultuous behavior displayed toward the public," he said. Once police had him on the ground, Shane said he believes the amount of force police used in trying to hold him down and handcuff him "appears to be reasonable."

But using the dog, Shane said, did amount to excessive force in his view, and could very easily have been deadly. Normal police procedure would have been to give the dog a "bite and hold" command, just to hold down a suspect. "I don't know of any training that allows police officers to launch the dog onto somebody's neck which is right where the dog went," Shane said, adding that a dog bite in the neck "could have killed him."

Atlantic City Mayor Lorenzo T. Langford released a statement Wednesday saying he found the video "quite disturbing."

"In an effort to ensure transparency and to maximize the level of scrutiny regarding the investigation of this matter, I am asking the State Attorney General's Office to oversee this investigative effort. Moreover, I will be making a formal request to the United States Department of Justice to monitor the investigation regarding this case," Langford said.

His statement specifically referred to the incident "involving the use of a K-9 dog," but made no reference to any of the officers involved or their actions.

The Castellanis' attorney, Jennifer Bonjean, called the videotaped episode "one of the most egregious examples of excessive force and police brutality" that she has ever seen.

"I am dismayed that we still have this problem where police officers are unwilling to speak truthfully and honestly when tragedies like this happen ... Every objective person who looks at this video, says 'Oh my gosh, this is unbelievable.' And (the police chief) will sit there and say, 'I stand by my officers.'" Bonjean said. "To me, I'm not surprised, it happens all the time, but it's still shocking and it's truly disappointing."

Connor Castellani, a six-foot-four-inch-tall media studies major, was charged with resisting arrest, disorderly conduct and aggravated assault on an officer and a canine.

Hospital photos show multiple wounds and dog bites on his head and neck, with more than 200 stiches needed to close his wounds, according to his family. He also suffered a crushed spinal nerve, numbness on the right side of the skull and several bruises and abrasions, his family said.

Despite his experience, Castellani says he still believes the majority of police officers are good people "who are here to protect us." But he hopes that his case will help bring more attention to law enforcement abuses.

"It happens on a daily basis, police brutality, and I think it just needs to be addressed and taken care of because it's just really wrong," he said. "I just happened to get one of the worst incidents of it."