TAMPA (FOX 13) - Matt Callahan's artwork has been seen all over the Tampa Bay area. Now, a Facebook post by his father, Mick Callahan, is what's getting people's attention.
Shared 350 times, the post offers a reward of $5,000 and names a person Mick believes killed his son.
FOX 13 won't name him because police have not called him a person of interest, but Callahan describes a trained boxer with a violent temper. He says the man punched his son outside the Fine Wine and Spirits Warehouse on March 11.
Matt Callahan died two days later.
"I will not sit back and allow people not to tell the whole story. We are providing incentive for people to do just that," said Callahan.
Mick Callahan says the man held a grudge after his son inadvertently offended him weeks before, during a game of pool.
"He simply sucker-punched my son and killed him," said Callahan. "How do you tell a 5-year-old his father is gone?"
Tampa police are aware the men had been acquainted before Callahan was found. They have not confirmed Callahan was attacked or how he was fatally injured.
But they are investigating, Callahan hopes with the help of witnesses who come forward thanks to his viral Facebook post.
"We all read about murders and horrible things in the paper everyday. But it doesn't affect you until it is a family member," said Callahan. "Then it becomes very very real."
Wednesday, someone added $3,000 to the reward.
Callahan was an organ donor, and four people are now living with the organs he donated.
FOX 13 reached the attorney for the man Callahan names, but he did not have any comment.