(CBS) — Just as his trial was about to begin, Lake County prosecutors dropped charges against a man accused of beating a family after cutting in line at Six Flags Great America last fall. Prosecutors said the victims were unable to testify, but charges might be refiled later.

Gregory Battle had been charged with aggravated battery and mob action, and was free on bail as his jury trial was about to begin on Monday.

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Before the trial, prosecutors announced the victims were unable to testify, due to the “medical consequences” of their injuries. Prosecutors left open the option to refile charges against Battle.

Gregory Battle (Credit: Gurnee Police)

Battle and eight other teenagers allegedly beat a 12-year-old boy and his parents waiting in line at the amusement park during “Fright Fest” on Sept. 23, 2017.

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Gurnee police said the melee started when the teens cut in front of a 50-year-old woman, her 51-year-old husband, and their 12-year-old son near the Raging Bull and Giant Drop rides.

When the woman asked the group to stop using obscenities in front of her child, one of the teens “sucker-punched” the boy.

Police said the boy’s parents stepped in to defend him, but the group overpowered them, and continued to punch, kick, and stomp them as they went down to the ground.

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Battle was the only suspect charged as an adult. Eight others between the ages of 15 and 17 were charged as juveniles.

The Batavia family injured in the attack also has filed a civil lawsuit against Six Flags, claiming amusement park workers didn’t do enough to prevent the attack.

The lawsuit states the family was at the park for “Fright Fest,” when an unknown male walked up to the boy and his friend, claiming to be security, and ordered the boys to follow him. The suit claims that person showed false credentials to the 12-year-old’s mother, and she started yelling for help, but Great America staffers “did nothing to intervene.”

A large group of young men and women began following the mother and shouting expletives at her, according to the lawsuit. After rejoining her husband, son, and son’s friend, she continued calling for security, when the group “viciously attacked” the family, but Great America employees still did not intervene.

Witnesses called 911, prompting the attackers to run away, the lawsuit alleges.

The family requested to remain anonymous because the son suffers from a disability, they fear reprisals if their names go public and the incident was “highly personal and sensitive in nature.”

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An update on the juvenile cases stemming from the attack was not immediately available Tuesday morning.