I've written a couple of answers about the internment of Japanese-Americans on here recently: this one was in answer to an almost identical question to yours.

In both answers, I recommended reading Personal Justice Denied, the highly critical report produced after the war by the Commission on Wartime Relocation and Internment of Civilians. It's all available online via the National Archive and Records Administration (see link above.)

To answer the second part of your question: conditions in the camps were far from desirable, but there wasn't a systematic programme of abuse and dehumanisation comparable to the German concentration camps.

There were isolated incidents of prisoners being killed by camp guards, usually in the context of either alleged escape attempts or escalated tensions between internees and the camp authorities. I'd suggest you look at chapter 6 of the Commission report — specifically the sections on camp security and internal tensions (pp174-180). Key extract:

The military police were solely for external guarding unless they weie called in by the project director to handle an emergency. Even so, they created problems in several instances. A [War Relocation Authority] investigation of Manzanar in the summer of 1942 reported:

The guards have been instructed to shoot anyone who attempts to leave the Center without a permit, and who refuses to halt when ordered to do so. The guards are armed with guns that are effective at a range of up to 500 yards. I asked Lt. Buckner if a guard ordered a Japanese who was out ofbounds to halt and the Jap did not do so, would the guard actually shoot him. Lt. Buckner's reply was that he only hoped the guard would bother to ask him to halt. He explained that the guards were finding guard service very monotonous, and that nothing would suit them better than to have a little excitement, such as shooting a Jap.

Some time ago, a Japanese [Nisei] was shot for being outside of a Center... The guard said that he ordered the Japaneseto halt-that the Japanese started to run away from him, so he shot him. The Japanesewas seriously injured, but recovered. He said that he was collecting scrap lumber to make shelvesin his house, and that he did not hear the guard say halt. The guard's story does not appear to be accurate, inasmuch as the Japanesewas wounded in the front and not in the back.

There were shootings at other centers as well. At Topaz, an elderly evacueethought to be escaping was killed. Mine Okubo described the incident:

A few weeks later the Wakasa case stirred up the center. An elderly resident was shot and killed within the center area inside the fence, by a guard in one of the watchtowers. Particulars and facts of the matter were never satisfactorily disclosed to the residents. The anti-administration leaders again started to howl and the rest of the residents shouted for protection against soldiers with guns.

As a result, the guards were later removed to the rim of the outer project area and firearms were banned.

At Gila River, a guard shot and wounded a mentally deranged evacuee. At Tule Lake, after segregation, an evacuee in an altercation with a guard was shot and killed.