Seven dollars - a $5 bill and two $1 bills - had been stuffed between his buttocks, according to investigators.
The money was scorched by the flames when the back of his undershorts burned away, they said.
"Obviously, he angered somebody," said Capt. John Apeldorn, head of the Police Department's Organized Crime Intelligence Unit.
"His killing looks like a message. Our job is to see if organized crime is involved, and just what the message is."
Among the leads being pursued by homicide and organized crime unit detectives yesterday was a report that Mazzuca was involved in collecting a ''street tax" for reputed mob leader Joseph "Skinny Joey" Merlino and had failed to turn over all he had collected.
Another was that Mazzuca had ties to a local drug operation and had balked at paying a street tax to the mob.
Still another theory was that Mazzuca had been killed in retaliation for a sexual encounter with a local mob figure's girlfriend.
George Borgesi, 31, a Merlino associate, was picked up for questioning at about 1 p.m. yesterday - but was later released by homicide detectives working the case. Borgesi, according to investigators, was seen riding in a white Lincoln near the murder scene shortly before Mazzuca's body was discovered.
Borgesi's lawyer, Michael W. Pinsky, said last night that his client, who was held for about four hours, "adamantly denied" any involvement in or knowledge of the murder.
"All he knows is what he heard on the radio," Pinsky said. "I think George Borgesi was picked up on the age-old theory of 'round up the usual suspects.' "
Mazzuca, whom police said had no criminal record, operated Samantha's Auto- Detailing in the 2400 block of Snyder Avenue in South Philadelphia. He lived in a two-story brick rowhouse in the 1300 block of South Second Street.
"He was a working guy," said Joseph Mazzuca, the victim's 31-year-old brother. "Somebody tried to ruin his business. Somebody must have been jealous or something. . . . People loved him, customers loved him. He's going to be missed."
Mazzuca had two young children by a girlfriend, his brother said.
Joseph Mazzuca said his brother was not involved with the mob and scoffed at the idea that the slaying was mob-related.
"It wasn't a mob hit," the brother said. But he added that whoever was responsible "would pay."
Among other things, police are looking into a possible link between the murder and an arson at Mazzuca's detailing shop earlier this month. Investigators say a car was set afire at the shop. The incident is still under investigation, and now detectives are wondering if it was a warning to Mazzuca.
"He knew he had a problem with somebody," said one law-enforcement source close to the case.
Capt. Stephen Glenn of the police Homicide Division described the killing as "an execution-style slaying."
Mazzuca was last seen alive around 11:30 p.m. Thursday, police said. They believe he was killed somewhere else, and his body was then taken to the 3500 block of Lawrence Street, where it was dumped and set afire.
The street, not far from the South Philadelphia Produce Center, dead-ends against a metal fence. Beyond the fence is a desolate, trash-strewn lot that leads to an underpass of Interstate 95.
Investigators believe the gasoline used to set Mazzuca's body on fire was purchased at a truck stop in the 3400 block of Lawrence. Detectives were checking out a report that two men stopped to purchase a dollar's worth of gasoline in a container shortly before the burning body was spotted at about 2 a.m.
Capt. Glenn said a patrol officer who first saw the flames thought it was a fire started by vagrants in an attempt to keep warm.
The officer went to investigate and saw that it was a body on fire.
The nature of the killing - the fact that the body was set on fire and that money was stuffed in the buttocks - was considered symbolic, and had several investigators recalling the 1980 slaying of mobster Antonio "Tony Bananas" Caponigro.
Caponigro, suspected of being behind the murder of mob boss Angelo Bruno that year, was lured to the Bronx, where he was brutally beaten and shot repeatedly. His body was stuffed into the trunk of a car and abandoned in the Bronx. Police found ripped $20 bills strewn about the corpse and stuffed into Caponigro's anus.
The money was said to be a message that Caponigro had been murdered because he was greedy.
The bills found yesterday on Mazzuca's body, investigators say, may have been a symbol of greed or a sign that he was killed over money. The fact that only $7 was left with the body, said another source, was a sign of disrespect.
"Maybe," said one investigator, "they're saying that's all this guy was worth."