Chicago rapper Twista was injured and his bodyguard, Arthur "Butch" Dixon, was killed when their van flipped over on a Pennsylvania interstate early Monday as the two headed home after a canceled concert.

Twista, whose real name is Carl Mitchell, suffered a bruised rib, cuts, and two black eyes in the crash, said his manager, who goes by the name Rawle.

Dixon, 45, son of the late blues legend Willie Dixon, was alive at the scene but died after he was taken by helicopter to a local hospital, Erie County District Attorney Brad Foulk said. Five others in the van sustained non-life-threatening injuries, police said.

"It's a miracle anybody survived," said Foulk, who arrived at the scene later Monday morning. "The top of the vehicle they were in was completely sheered off ... it rolled four, possibly five times."

Twista, 30, who grew up in Chicago, had a No. 1 hit earlier this year with his song "Slow Jamz." His album, "Kamikaze," released in January, has sold more than 1 million copies.

Dixon, an accomplished pianist who just months ago played with Chuck Berry at a Chicago concert, had served in recent years as a bodyguard for both Twista and R. Kelly, relatives said.

"He loved music," said blues singer Koko Taylor, who had known Dixon since he was a baby. "That's the reason he was in the [van]."

Police said the accident occurred around 4 a.m. Monday on Interstate Highway 90 about 5 miles west of the Ohio line. Band members were driving home after their show in Albany, N.Y., was canceled so fellow rapper LL Cool J could be with his wife, who had surgery last week, according to the Web site for Pepsi Arena.

Investigators on Tuesday were still trying to determine what caused the single-vehicle accident. All six passengers were ejected onto a grassy median in the middle of the interstate, Foulk said. Only the van's driver, Twista's cousin Otis Bankhead, was wearing a seat belt when the accident occurred, he said.

Rawle said Twista was "banged up pretty bad" in the accident but was more hurt emotionally by the death of Dixon.

Dixon's mother, Marie, said her son grew up on Chicago's South Side surrounded by blues legends. Taylor was a neighbor to the Dixon family home in the 7600 block of South Throop Street, and members of his father's band, the Chicago Blues All Stars, were constantly nearby.

Although named after one of Willie Dixon's brothers, Arthur Dixon was known by friends and family as "Butch" or, in some cases, "Big Butch"--a nickname given by saxophonist Harold Ashby.

"He was a happy-go-lucky kid," Taylor said. "He was always wanting to kid and play."

Marie Dixon said her son dreamed of being a football player, but her husband insisted all his children learn an instrument. Butch Dixon chose piano and was trained by pianist Lafayette Leake, then a member of Willie Dixon's band.

When he was old enough, Butch Dixon began touring with his father, hitting blues clubs throughout North America and Europe. He continued until 1990, when his father semi-retired from the business, Marie Dixon said.

"He enjoyed it," she said. "Once he traveled with his father and learned different cities and states that they went to, he seriously enjoyed being out there and playing the piano."

Billy Branch, who played the harmonica with Willie Dixon's band when Butch Dixon was just starting out, said he used to call Butch "Baby Boogie."

"I was `the Boogie Man.' He was kind of patterning himself after me," Branch said. "He said `you'll be "the Boogie Man," I'll be "Baby Boogie."' He had gotten to be quite a piano player."

Marie Dixon said her son worked briefly as a Cook County sheriff's deputy after Willie Dixon died in 1992. In the years since, Butch Dixon had continued playing the piano and occasionally the drums. As recently as June, he played with Berry at an Academy of Achievement Conference at the Field Museum, friends said.

In recent years, Dixon spent the bulk of his time helping his family's non-profit organization, the Blues Heaven Foundation, and working as a bodyguard for Twista and other artists.

Rawle said Dixon started working with Twista after the two talked earlier this year at a voter registration event in Chicago.

"He knew how to handle business and at the same time he was courteous, not just a bodyguard with a lot of muscle," Rawle said of Dixon. "In my eyes, security work was just a side thing to him, but he took it seriously."

Barry Dolins, coordinator of the Chicago Blues Festival, said he had seen Butch Dixon Thursday during a chance meeting in the Loop. He said he had tried to call him later but Dixon was already out of town.

"It's just an untimely death," Dolins said. "I think he had a lot of great ideas and plans still ahead of him."

Marie Dixon said her son was married and had three children. Funeral arrangements were pending.