The state has fired a probation officer and three of his supervisors for missing key opportunities to lock up a violent ex-convict before he became the suspected mastermind of a home invasion that left six people dead — supposedly over an Xbox (search) video game system.

Corrections Secretary James Crosby said the officials let the suspect, Troy Victorino (search), slip through the cracks when he should have been behind bars long before Friday's slayings.

"There is no excuse for this inaction," Crosby said Monday.

Victorino's probation officer let him leave a regular appointment even though Victorino should have been detained for violating his probation for allegedly punching an acquaintance in the face in a dispute over money, state officials said.

"I think somebody, somewhere dropped the ball," said Mark Shukwit, the stepfather of 19-year-old Michelle Nathan (search), one of the six people beaten and stabbed to death early Friday as they slept.

Victorino, 27, and three teenage defendants have been charged with first-degree murder and armed burglary. The four were denied bond and appointed public defenders Monday during their first court appearance.

Since his release from prison in 2002 on battery and grand theft charges, Victorino, 27, has been accused of battery, a hit-and-run and making harassing phone calls. Yet each time, he managed to stay out of jail, court records show.

Victorino was arrested July 29 — a Thursday — on a felony battery charge, accused of punching a man over a car debt. He was released on $2,500 bond, and sheriff's deputies filed a routine report with the probation office the next day.

The probation office was supposed to send a report to a judge requesting an arrest warrant for probation violation within 48 hours of getting the police report, Crosby said. But instead of that being done on that Monday, the paperwork was not filled out until last Wednesday. It wasn't taken to the courthouse until last Friday, when the judge issued an arrest warrant, court records show.

The report outlined the facts of Victorino's July 28 alleged crime and July 29 arrest, noted that he was on probation for a violent battery and said he appears to be "a threat to the community." It recommended that he be put in jail.

That recommendation was not carried out during Victorino's regular check-in last Thursday and Crosby said he had no answer for why Victorino was able to walk away. Within hours, the six victims, who ranged in age from 18 to 34, were dead.

Crosby fired Victorino's probation officer, who specialized in handling violent offenders; an administrator in charge of four counties in northeast Florida, and one of three regional probation directors in charge of northern Florida. All four men had been with the corrections department or probation system more than 20 years each.

Police said the killings were the brutal culmination of an argument between Victorino and one of the victims, whom officials identified Monday as Erin Belanger, 22. She was singled out for a beating so brutal that even dental records were useless in trying to identify her.

Authorities say the source of the dispute was an Xbox video game system and clothes owned by Victorino. Belanger's grandparents own a Florida winter home that was supposed to be vacant this summer, but police said Victorino and other squatters used it in July as a party spot.

The squatters were kicked out, but they left behind the Xbox and clothes. Belanger took the items back to the three-bedroom rental home she shared with friends. Investigators said Victorino organized the attack to retrieve the items.

Some relatives of the victims attended Monday's hearing. Victorino kept his head down during the proceedings. "I wanted to see this. I wanted to see who murdered my daughter," said Kay Shukwit, mother of Nathan. "I want to look at him."