Editor's note: Nearly three years after President Obama declared the Guantanamo prison for terrorist suspects would be closed, the camp in Cuba remains open. Of the more than 750 inmates that were once held there, fewer than 200 remain now. CNN contributor Jenifer Fenton interviewed some of the former inmates, and one of the guards.

(CNN) -- "We were told that they were all guilty ... that these were the worst of the worst," Brandon Neely said about the detainees who were arriving at Guantanamo Bay, Cuba.

"We were told that these guys, all of them, had either helped plan 9/11 or were caught red handed on the battlefield, weapon in hand, fighting American soldiers ... These are the people that would kill you in a heartbeat if you turn your back on them."

In June 2000, Specialist Neely, now 31, enlisted for five years as a military police officer. He left later that summer for Fort Leonard Wood, Missouri for training and was assigned to Fort Hood, Texas upon graduating. In early January 2002, Neely boarded a plane to Guantanamo Bay, where he would be stationed for the next six months. He had volunteered for the deployment not knowing what it was or where it would take him.

"I was asleep in my barracks one morning. They knocked on my door and ... told me there were two deployments that were going to happen in the deployment area."

Neely agreed to go on one and then went out with his friends later that night. The next day, he was informed that he would be stationed at Guantanamo. "I was kind of mad that I was going to go to Guantanamo instead of the front lines of the war," Neely recalled.

His superiors told him he would be stationed a detention facility, Neely said. "They had decided from the start that it was different from an enemy prison of war camp ... We were told in the first couple of minutes at Gitmo that this was a detention facility and the Geneva Conventions would not be in effect ... There was no army manual on this, no standard operation procedure."

Neely did not receive any special or additional training for working at Guantanamo, he said. He, and the rest of the company (about 110 people), arrived just a few days before the first detainees did. Contractors "were still welding the cells at the time," he said.

As a military policeman, Neely was not involved in interrogations. The company's assignments included escorting duties -- taking detainees to the showers or a medical examination and filling the water buckets in the cells.

"At Camp X-Ray you would have to take a water hose and put water in their buckets ... They had two buckets, one for water and one to use as the restroom," Neely said. Personnel could also be assigned to check identifications or to the Internal Reaction Force team. The jobs rotated on a daily basis for the most part.

On January 11, the prisoners began to arrive. "We were told those [detainees] were the top guys. This is the group that they had to get out of Afghanistan because they were literally the worst of the worst," Neely said. He was not sure what to expect.

"I didn't really understand what a terrorist was going to look like. I know that sounds funny and really naive. I was kind of shocked that a lot of them were very little and malnourished." Neely remembered commenting at the time: "If these are the world's most dangerous men, we don't have very much to worry about."

The detainees were wearing blacked out goggles, leg shackles, three-piece suits and ear muffs. Some had gloves on, Neely said.

There was an incident on the first day that he was involved in. He said after the detainees were processed, their pictures and fingerprints were taken and they were given a quick check over. Then they were to be escorted to their cells.

Neely said he and his escorting partner were taking one detainee assigned to Alpha Block. They started to walk but the detainee was shaking and would not walk. "So we started yelling and screaming at him to walk faster ... We were actually walking so fast and he wouldn't walk so we had to pick him up off the ground and we were carrying him."

The detainee was put in his cell with Neely taking control of his upper body. His leg shackles and right handcuff were taken off. Neely said when he went to take off the left handcuff the detainee jerked toward him.

"We started yelling at him and screaming at him not to move," Neely said. Neely said the detainee continued to jerk when he and his partner tried again to remove the cuff.

"Next thing I know I slammed him on the ground and I was on top of him. He was trying to get up. I kept pushing his head down to the... concrete floor." Neely said he could hear people on the radio calling "code red Alpha Block." His escorting partner had backed out of the cell and closed the cell door.

"It was just me and the detainee in there." The IRF team "opened the cell door, grabbed me by the back of my uniform and pulled me outside and they just went in there hogtied him and left him there for I don't know how long."

A few weeks later, Neely said he was told by one of the English-speaking detainees why the man kept moving. "The reason he had moved was not to fight... He still had the blacked out goggles on so he could not see. He thought he was going to be executed," Neely said. "A lot of those guys thought they were going to be executed when we put them on their knees and started talking their cuffs off."

Neely said he felt ashamed. He said he witnessed abuse by the guards and others during his six months at the camp.

He said in one incident that occurred in the first few weeks at the camp, a detainee refused to drink a can of the protein drink Ensure, which many detainees were given because they were malnourished. The IRF was called to restrain the detainee so a medic could give him the drink. Upon entering the detainee's cell, one of the IRF team hit the detainee with a shield, Neely said.

The entire team was soon on top of the detainee so it was difficult to see what has happening, according to Neely. The IRF team then stood the detainee up and handcuffed him to the cage fencing and the medic entered the cage, grabbed the detainee by the neck and emptied the can of Ensure into his mouth, but he detainee did not swallow it, Neely said.

The medic then punched the detainee and walked out of the cage like nothing had happened, he added. The detainee was un-cuffed from the cage, hogtied and left that way for several hours, according to Neely, who said he later learned that the detainee thought he was being poisoned.

In another incident, when the camp had been operational for about two months, a detainee allegedly made a comment about one of the female guards and the IRF team was called to Bravo Block.

"They went up to the cell door and they told [the detainee] to turn around and put his hands on his head. He didn't listen," Neely said. The IRF team unlocked the cell door, at which point the detainee turned around put his hands on his head and went on his knees.

The IRF team opened the cell door and the one team member carrying a riot shield threw it off to the side. "And whatever little speed he could gather from that short distance he jumped up in the air and came down with his knee right in the middle of the back of [the detainee] and landed right on top of him."

The other four men started punching the detainee. "Then someone on the inside called the female MP... in there to hit him. And she did," Neely said.

When it was all over the detainee was in a pool of blood unconscious, according to Neely. The detainee was taken by ambulance to the main hospital in Guantanamo. The detainee was later released from Guantanamo Bay without charge, Neely said.

Asked about the allegations, a U.S. military spokeswoman told CNN via email that the Department of Defense does not tolerate the abuse of detainees and takes such allegations seriously. She however denied there was a pattern of systematic mistreatment.

"All credible allegations of abuse are thoroughly investigated, and appropriate disciplinary action is taken when those allegations are substantiated," Cmdr. Leslie Hull-Ryde said.

But she added: "Although there have been substantiated cases of abuse in the past, for which U.S. service members have been held accountable, our enemies also have employed a deliberate campaign of exaggerations and fabrications. The suggestion that DoD personnel, the overwhelming majority of whom serve honorably, are or ever were engaged in systematic mistreatment of detainees is false and does not withstand scrutiny."

As for Neely, he still recalls his conversations with the detainees who spoke English.

"I was always kind of worried about them because of all the stuff I had heard," Neely said. "We were told they were all guilty." The two prisoners he spoke to the most were former British detainees Ruhal Ahmed and Shafiq Rasul. At Guantanamo, they would talk about music and normal subjects. "Eminem and Dr. Dre... at the time [they] were real big," Neely said.

Ahmed "would tell us he was from London. It was kind of weird, because here this guy was in Guantanamo behind this cell door and here I was on the outside ... He was actually doing a lot of the same stuff that I was doing in the United States ... We had a little bit in common."

Ahmed and Rasul were released from Guantanamo and transferred to Britain in 2004. They sued for damages against Donald Rumsfeld, the former U.S. secretary of state, and other senior military officers over alleged inhumane treatment at Guantanamo. The case was dismissed because the alleged abuse occurred before the U.S Supreme Court said that the constitution covered detainees in Guantanamo.

Neely returned to Fort Hood after his six-month deployment at Guantanamo was up. When he left, he signed a non-disclosure statement -- which he said was routine -- stating that he would not talk to the press, write a book or make a movie. He was told he could be prosecuted if he did, but has gone public about his concerns because he disagrees with U.S. policies in places like Guantanamo and Iraq. He has also testified to the Center for the Study of Human Rights in the Americas at the University of California, Davis.

"I have no problem fighting and dying for this country, but I am not going to kill or be killed for something I don't believe in," he said.

Neely deployed to Iraq in 2003, returned to the U.S. the following year and left the military in 2005, when his contract was up. In 2007, Neely did not respond to a recall for active duty and he was honorably discharged. He now works as a police officer in Texas, where he is raising three children.

He thinks the detention center should be closed. "I think someone would be naive to say that everybody that ever stepped foot in Guantanamo was innocent," Neely said. We know they are not, but "the fact is there is a better way to do it ... you can't just throw the principles and the values of the country and the law of the land out the window because it benefits you." Detaining innocent people and depriving them of their due process is "a significant black eye on the Unites States," Neely added.

There will be a time and a place when Neely will tell his children -- the oldest is now 10 -- about Guantanamo. I will "give them all the information and let them make their own opinion ... I'll just tell them the truth ... I will tell them that I have been part of it."

Neely initially contacted Rasul via Facebook and then met with Ahmed and Rasul, the two former British detainees, in London almost two years ago.

Neely wanted to get in touch with them to say that he was sorry for the part he played in their detention at Guantanamo. "I was very nervous to meet them," Neely said. He did not know what might happen. "I wasn't sure if they would hate me, yell at me," he added. "I can honestly say though when I left London I left with two more friends then I arrived with."