Tuesday, he talked to ABC7 about the attack and the friend he lost.
Viverito was in Jacksonville with Chris Pettry, of Lake Villa, his best friend since elementary school.
Now, Viverito and Chris Pettry's family members are waiting for answers into what happened inside the bar that ended in his death.
Viverito flew home from Jacksonsville Monday night from a weekend that turned tragic without any explanation. Viverito says he and his best friend were sitting at an outside table at a bar just a couple blocks from their hotel.
Viverito says Pettry went inside to use the restroom. Minutes later the 42-year-old father of three was dead.
"Why this happened to him, it doesn't make sense," said Viverito.
Viverito has no idea why his best friend was killed inside a Jacksonville bar.
Viverito and Pettry knew each other since the third grade. Once a year, both try get to get away for a sports-related weekend. Because Viverito has family in Jacksonville, he invited Pettry to come with him to see the Bears on the road.
"He couldn't wait," Viverito said. "That is all he talked about the last couple weeks, 'I can't wait for Florida, can't wait for Florida.' "
But Viverito says it wasn't easy for Pettry to get away from work and his family. The 42-year-old was an independent contractor who worked six days a week, often 18 hours a day.
"He was working the morning we flew out," said Viverito. "I almost had to take the hammer out of his hand."
The night before Sunday's game, Viverito and Pettry went to a popular tourist area in Jacksonville called Jacksonville Landing. They sat outside on the patio of a restaurant and bar. Viverito says that is where they met the man accused of killing Pettry, Matthew Hinson.
Viverito says Hinson was meeting his wife and her friend. They all sat at Viverito and Pettry's table for a brief time.
"He sat at our table, shook our hands, introduced himself and then after a few minutes he, his wife and their friend went inside," said Viverito.
About an hour and half later, Viverito says Pettry went inside to use the restroom and buy another round of drinks. After 20 minutes, Viverito was wondering where his friend was, until a waitress came running out and told him Pettry was inside not breathing and bleeding.
"There he was laying in a pool of blood," said Viverito. "People were working on him, trying to revive him."
Police say Hinson slashed Pettry's throat with a small pocket knife and calmly left the bar. Hinson was caught a short time later and confessed to the crime. Hinson has been charged with murder and is being held without bail. He has no prior criminal record.
"Why? Chris is not a fighter," said Viverito. "He is not confrontational. What could have set this guy off?"
Originally, Hinson told police he didn't know why he killed Pettry. But, later, Hinson apparently told police he became enraged when he saw Pettry talking to his wife.
Veverito doubts that is the motive because his friend only spoke to Hinson's wife for a brief time.
Viverito calls his a friend a great guy who would do anything for his friends and family.