It remains unclear what prompted the fight. At least eight people have been arrested and charged in connection with Henderson's death, authorities said.
Tiara Henderson, Bakari Henderson's cousin, said in a Facebook post Friday that his death was the result of a “senseless crime” and “horrendous actions by the perpetrators.”
Surveillance videos from nearby shops showed the suspects beating Henderson even after he was unconscious, ANA-MPA reported. The recent University of Arizona graduate later died at a hospital.
A 32-year-old from Serbia and a 34-year-old from Greece were arrested shortly after the fight, ANA-MPA reported. Media reports said that the 32-year-old is a British citizen of Serbian origin, and that both men worked at the bar.
The six others, all from Serbia, were arrested later after they were recognized from surveillance videos and police raided the hotel where they were staying.
Henderson's friends have created a GoFundMe page to raise money for his funeral and to return his body to the United States. More than $29,000 had been raised as of Sunday evening.
“The love for this young man overflows and this loss is unbearable for so many of us,” according to the page. “If you knew Bakari you knew he was driven in life and no goal is never set to high for him to achieve. He was just starting his life, so many dreams and aspirations yet to be achieved.”
Travis Jenkins, a friend, told ABC News that Henderson was not the type to start a fight.
“Bakari was not one to act aggressively like that. He was always the one who was the peacemaker,” Jenkins said.
Jan Richardson, the family's spokesperson, said they hope to bring Henderson's body to the United States early this week.
“The family is coping by trying to have a large support group. We're in close touch with each other physically ... and leaning on God for direction,” Richardson told The Washington Post.
Several friends have since changed their Facebook profile pictures to those of them with Henderson.
“Absolutely heartbroken. Miss you already B,” Sam Hindsman wrote Friday.
Alyssa White posted a picture of her and Henderson with a big smile.
“I miss that smile more than anything. Thank you for countless hours of life talks and inspiring me to open my mind. I'll miss every second but I promise to celebrate your life each and everyday,” she wrote Saturday. “Bakari, you are the best friend I will ever have and I love you forever and ever.”
Phoebe C. Wadsworth, associate athletic director for the University of Arizona, said Henderson was her former student.
Henderson, who was from Austin, was in Greece for a photo shoot to launch his new clothing line, his family said in a statement. He attended Arizona on a full academic scholarship and graduated in May with a bachelor's degree in business finance and entrepreneurship, along with a certificate in sports management. He also had internships with the Texas legislature, including the House speaker's office, his family said.
“As you can imagine, our family is devastated by the recent loss of our beloved son Bakari Jaward Henderson,” his family said in the statement, adding later: “Bakari loved spending time with family and friends, traveling, and meeting new people. He was a big thinker and enjoyed coming up with new business ventures. Bakari was an inspiration to all he met. He loved life to the fullest.”
Autopsy results are pending, but Kathimerini, an English newspaper in Athens, reported that Henderson was taken to the hospital with severe head injuries.
Pavlos Kolokotsas, mayor of Zakynthos, told the publication that the island often attracts alcohol-fueled fights. Zakynthos, the third-largest island in the Ionian Sea, is known for its crystal-clear waters, limestone cliffs and a nightlife that draws young tourists.
University of Arizona President Robert C. Robbins said in a statement that the school is “shocked and saddened” by Henderson's death.
“Our hearts and prayers are with his friends and family. I can only imagine the deep sense of loss they must be feeling at his untimely death,” Robbins said. “It is always a tragedy when a young life ends before it has really yet to begin.”
A State Department official said Saturday that Greek police have notified the U.S. Embassy of Henderson's death.
“We are in communication with authorities and providing consular assistance to the deceased citizen's family,” the official said. “We offer our sincerest condolences to family and friends, and out of respect for the family during this difficult time, we have no further comment.”
Sen. Jeff Flake (R-Ariz.) said Friday night that he is in touch with State Department officials to make sure Henderson's friends get home safely.
In another statement, Rep. Martha McSally (R-Ariz.) said: “My thoughts and prayers are with the family and loved ones of Bakari Henderson, whose life was senselessly and brutally cut short this weekend. The loss of our recent University of Arizona graduate is truly tragic and shocking, and I offer my deepest condolences to all who knew him.”
This story, originally posted on July 8, 2017, has been updated.