Six men have been convicted of various assault charges and sentenced by a Greek court in the brutal beating death of American Bakari Henderson. The verdicts handed down on Thursday were a blow to Henderson's family, who had hoped for murder convictions. The rulings have been appealed by a Greek prosecutor.

CBS News correspondent Charlie D'Agata reported that Henderson's parents were in the courtroom on Thursday as the sentences, ranging from five to 15 years in prison, were handed down.

His mother Jill Henderson said ahead of the court session that she and her husband Phil were, "just hopeful that justice will be served, and that all defendants will get life sentences."

After the sentencing, Phil Henderson told CBS News outside the court that he, "can't understand, a man's life here in Greece doesn't mean anything."

"You should not be able to chase a man down and beat him to death and not go to jail," his wife added, before breaking down in tears.

There were nine defendants on trial -- seven Serbian nationals, one Greek and a Brit of Serbian origin. Three were exonerated, and all claimed they had not intended to kill Henderson.

The British national was given the most severe sentence, of up to 15 years in prison for causing grievous bodily harm. One of the Serbs was sentenced to 10 years, three got seven years and another five years, all for lesser assault charges.

D'agata reports the defendants were seen smiling, hugging and exchanging high-fives in court after the verdicts were read.

Bakari, a 22-year-old recent business graduate from the University of Arizona, was in Greece last year on a working holiday with friends. He was planning to shoot promotional video for his own line of apparel.

On the night in July 2017, he ran into the defendants at a bar. A Serbian woman told investigators that when she posed for a selfie with the American, a man nearby said, "There are a lot of Serbs in the bar. Why are you talking to a black guy?"

She said the man then smacked Henderson in the face, and Henderson hit him back.

The brawl moved outside, where a mob of men chased him down the street, brutally beating him.

Just 30 seconds later, Henderson was dead.

In an interview with "CBS This Morning's" Michelle Miller before they left the U.S. to be at the trial, Henderson's parents said they believed race may have played a role in their son being beaten to death.

"His face was bruised and swollen," Jill told CBS News, "to the point where we put sunglasses on him when we buried him."