A chiropractor with a criminal past has been charged in the beating death of an elderly Connecticut man who was attacked inside a Stamford parking garage.

It's unclear what sparked the confrontation or whether William Lindemann — who lives in Florida and has been trying to sell a Greenwich house he owns, according to police — knew his alleged victim.

Police traveled to Florida on Tuesday to pick up Lindemann, 47, who was arrested Friday at his Naples home on a first-degree assault charge. Lindemann was convicted a dozen years ago in an insurance fraud scheme with suspected mob ties in New York.

Herbert Davison, 79, died Sunday from head injuries he suffered in the Jan. 27 attack. Authorities expect to upgrade the charge against Lindemann to at least manslaughter, said Stamford police Capt. Richard Conklin.

Police say the two got into an argument as Davison was heading to a poetry night at a local restaurant.

Conklin said Tuesday that police were withholding details of the case because they had not questioned Lindemann. He declined to comment on what prompted the fight or how the two men knew each other.

Davison's son, Bruce Davison, said Tuesday that he and other relatives do not know Lindemann. He said he wasn't sure how the fight started.

"They met in the parking lot and had words of some sort," Davison said. "Whether it was road rage or something of that nature — somebody cut somebody off — that's all we can think of."

He described his father as twice-married retired engineer with five children and seven grandchildren who enjoyed writing poetry.

Lindemann is expected to be back in Stamford by Wednesday for questioning and a possible court appearance, police said.

Ross Pearlson, a New Jersey defense lawyer who represented Lindemann in the insurance fraud case, said he hasn't spoken with Lindemann in years. He said he was surprised to hear about Lindemann's arrest.

"He had no violence in his past," Pearlson said.

When Lindemann was indicted in the fraud case in 1997, federal prosecutors in New York suspected him and other medical professionals of collecting health insurance money for patient visits and treatments that never occurred, according to a 1997 New York Times report.

Authorities believed the fraud scheme involved people with ties to the mob, the Times reported.

He was later convicted, sentenced to 16 months in prison and released in April 2000.

Prosecutors never proved that Lindemann had any connection to organized crime, Pearlson said.

Lindemann is a New York-licensed chiropractor who practiced in Brooklyn, according to New York state records. Records show his license was suspended in 2001 for two years after he admitted to having been convicted of seven fraud counts.

It was not clear Tuesday if Lindemann was still involved in the Brooklyn practice. A phone number at the office was busy throughout the day.