ORLANDO (CNN) — The family of Robert Champion, who died in November after he was beaten on a bus, allegedly as part of a Florida A&M University band hazing ritual, will sue the bus company, their attorney said Tuesday.

The bus and its air conditioning system is believed to have been running at the time Champion was beaten, attorney Chris Chestnut said, and the bus driver might not have been aboard. The family is suing Fabulous Coach Lines, based in Branford, Florida, he said.

“We do anticipate, in the very near future, filing a legal action against the bus company alleging negligence and wrongful death,” Chestnut told reporters at a news conference Tuesday.

Such a lawsuit will allow him to file subpoenas and take witness statements to further the investigation, he said. Part of that investigation will include determining what bus company employee was assigned to the bus, how it was running and how an estimated 30 people were on the bus long enough for Champion to be beaten to death.

FAMU is protected under sovereign immunity, and the family must file a statutory notice of intent to sue and wait six months to file suit against the school, Chestnut said.

A CNN call to the owner of the bus company Tuesday was not immediately returned.

Some band members have said Champion, 26, died after taking part in a rite of passage called “crossing Bus C.” Chestnut said Tuesday he’s heard the ritual may have happened before on Fabulous Coach Lines.

One member, who spoke on condition of anonymity, previously explained that students “walk from the front of the bus to the back of the bus backward while the bus is full of other band members, and you get beaten until you get to the back.”

“We’ve spoken to a lot of people,” Chestnut said, “in excess of 15 people.”

Friends of Champion have told Chestnut during his investigation that Champion was gay, the attorney said.

Relatives believe that may have been one of many factors that contributed to his being treated more severely than other band members, Chestnut said.

However, he said, Champion’s homosexuality is not believed to have been a primary factor in the beating.

“This is not a hate crime. This is a hazing crime,” he said. “Florida A&M University has a 50-year history, a culture in this band, of hazing.”

The family thinks some people might have been jealous of Champion, a stickler for the rules who stood up against hazing, he said. “Robert Champion was defined by the fact that he followed the rules,” Chestnut said.

Champion also may have been about to become the band’s lead drum major, Chestnut said. Band director Julian White, who’s on administrative leave from his post, said at Champion’s funeral November 30 he regretted not telling him he had been selected to be the band’s next head drum major.

Champion’s mother, Pam, told reporters Tuesday her son “loved his music. He loved the band. He was very serious about how he did and the position he was in.”

Champion collapsed in Orlando on the bus, which was carrying members of FAMU’s Marching 100 after a November football game that included a halftime performance by the group.

Chestnut has charged that Champion died after receiving “some dramatic blows, perhaps (having an) elevated heart rate” tied to “a hazing ritual” that took place on the bus.

The medical examiner’s office ruled his death a homicide and said Champion “collapsed and died within an hour of a hazing incident during which he suffered multiple blunt trauma blows to his body.”

An autopsy conducted after his death found “extensive contusions of his chest, arms, shoulder and back,” as well as “evidence of crushing of areas of subcutaneous fat,” which is the fatty tissue directly under the skin.

“When a crime victim is targeted because of his or her identity, it can have devastating effects on communities,” said Michael Cole-Schwartz, spokesman for the Human Rights Campaign. “The allegation that Robert Champion may have been singled out because of who he was must be thoroughly investigated and prosecuted accordingly.”

The death prompted the FAMU board of trustees to approve a new three-part anti-hazing plan.

The new policy was passed in a 9-1 vote by the board last week as the school continues to deal with the controversial death.

Champion’s mother told reporters she wants hazing to stop.

“Think twice when your kids are going off to college,” she said. “Look into what’s going on at their college … Now we know.”

Along with the university, the Florida Department of Law Enforcement and the Orange County Sheriff’s Office are also investigating the case.

Chestnut said law enforcement has not contacted Champion’s family and they don’t know the status of the criminal investigation.

The Florida Department of Law Enforcement has launched a separate investigation into some school employees, who were allegedly engaged in financial fraud.

— CNN’s Vivian Kuo and Ashley Hayes contributed to this report.