Ben McRea was a groomsman in Justin Ross Harris' wedding, but now says he is sickened by his former friend.

Although McRea initially felt "terrible" for his friend for the loss of his son in a hot car death, he now thinks Harris is a "monster," and that the death was not an accident.

Harris was charged with murder and second-degree child cruelty after leaving his 22-month-old son, Cooper, in a hot car for seven hours on June 18. The temperature reached 92 degrees on that Atlanta day.

McRea said he was saddened by the circumstances, and felt for his long-time friend.

"Ross was family to me. I loved him like a brother," he told WBRC on Friday.

Soon after Harris' arrest, however, details emerged that changed McRea's feelings toward his friend.

Cobb County Police Detective Phil Stoddard testified that Harris sent nude photos to multiple women and teenagers on the day of Cooper's death. In addition, he researched prison survival on the internet, and watched videos of children dying in cars. He also visited a website that advocates not having children.

Harris' wife, Leanna, also researched child hot car deaths before Cooper's passing. The couple claims the research was because they were afraid that it would happen to their son. Leanna has not been charged with a crime.

McRea was horrified by the revelations.

"It was sickening," he said. "It really broke my heart. It was really totally against the type of moral character I thought he had. I'm just totally disgusted with his behavior, ashamed, very ashamed."

He expressed feeling deceived by his former friend.

"It's almost like he's a monster and I'm like what happened? When did you become this person that we see on TV now? Or were you always like this and just hid it that well?" he wondered.

Despite his anger towards Harris, he said that the loss of Cooper is most devastating.

"I just don't want baby Cooper to be forgotten," he said. "I want there to be justice for the suffering. What he had to go through."

Harris has pled not guilty to the charges against him, and is being held without bail in Cobb County Jail.