Decatur, Georgia (CNN) -- Somber chords sounded at a funeral service Wednesday for a drum major whose death has sparked an investigation of hazing allegations at his Florida university.
Criticisms of hazing and rallying cries for change echoed throughout the three-hour church ceremony.
"I call on every mother, every father, every niece, every uncle: Do what is necessary now to stop this tragedy so that it will never happen again," the Rev. John Tatum shouted into a microphone as he pointed at hundreds of people packed into the pews at Beulah Missionary Baptist Church in Decatur, Georgia.
Authorities have not specified what caused 26-year-old drum major Robert Champion's death after a performance earlier this month with the Marching 100 band from Florida Agricultural and Mechanical University (FAMU). Officials said hazing was involved, and his family has said it plans to sue the school "to get answers."
Speaking at Wednesday's service, FAMU President James H. Ammons pledged to "wage a campaign to stomp out hazing on the campus at FAMU," drawing cheers and applause from the crowd.
"I vow as president of FAMU that Robert's death will not be in vain," Ammons said.
Music and testimonials filled the service for Champion.
A band performed from Southwest DeKalb High School, where Champion first became a drum major at the end of his sophomore year. As a recording of "Flight of the Bumblebee" from the soundtrack of the 2002 movie "Drumline" played, audience members stood and pantomimed performing the song on band instruments.
A jazzy trumpet solo marked the funeral's final moments.
Several speakers described Champion as a kind person and a strong leader who was dedicated to achieving his goals.
"Robert gave us his all every time that he took the field. ... Whenever Robert heard the sound of the drum, his knees raised, his toes pointed and he was on a mission to make the FAMU community proud," said Julian E. White, who has led the 420-member FAMU band since 1998.
The university's president moved to fire White shortly after Champion's death, citing "alleged misconduct and/or incompetence involving confirmed reports and allegations of hazing with the Department of Music and the 'Marching 100.'"
White has hired an attorney to fight for his job and has said he did everything he could to put a stop to hazing.
White made no mention of the allegations at Wednesday's funeral. He said that he considered Champion a son and regretted not telling him he had been selected to be the band's next head drum major.
"I loved that young man. The world is a better place because of Robert Champion," he said.
While uncertainty swirled over the hazing allegations, there was no doubt among mourners Wednesday that Champion was doing what he loved. A program distributed at the service showed several photos of him performing with FAMU's band.
Inside the program, an obituary said Champion proclaimed his goal of becoming a drum major in the Marching 100 after seeing them perform when he was just 5 years old.
His childhood next-door neighbor described memories of watching Champion marching around his yard.
Mourners filing past the open coffin before Wednesday's service began saw Champion's body clad in the band's uniform, his hand holding a baton.
A group of drum majors draped his coffin with the university's flag as the service began.
Band members who attended FAMU decades ago were among those who attended the ceremony.
Brian Joyner, 49, said after the service that Champion was kind and humble when they met at a recent homecoming game. The hazing allegations are "baffling" for many of the prestigious band's alumni, said Joyner, who was a drum major in the band in 1980.
"There's nothing I've heard of in 32 years where a drum major was required to go through any type of initiation," he said.
He defended White, the band's longtime director.
"The rumors that you hear about Dr. White not being active and eradicating hazing, that's a lie," he said.
Wednesday's service came two days after Champion's family said they would sue FAMU.
"We are concerned about the culture of cover-up, that hazing has been covered up...for generations," the family's lawyer, Chris Chestnut, said Monday.
The medical examiner has not issued a report on the cause of death of the 26-year-old student. But, Chestnut said, evidence points "to the fact that hazing was a cause of Robert Champion's death, and it was under FAMU's watch."
Champion became ill at an Orlando hotel after a football game on November 19. He reportedly vomited in the parking lot and started complaining of not being able to breathe, authorities said.
Champion was taken to a hospital, where he was pronounced dead.
Orange County Sheriff Jerry Demings said last week that hazing was involved, but added that authorities were trying to determine an official cause of death. Under Florida law, any death that occurs as the result of hazing is a third-degree felony.
After the death, Ammons suspended all band performances and said he would convene a task force "to determine if there are any unauthorized and questionable activities associated with the culture of the Marching 100."