The attack from last week at Brownie's Pub was caught on tape, but it may have been the quick actions of other bar patrons that helped bring the suspect into custody.
On the video the victim is seen in a white T-shirt sitting down at a table.
"The victim was just sitting there minding his own business," said Supt. Michael Chitwood of the Upper Darby Police.
His attacker stands behind him, then suddenly reaches down and slashes the victim's throat.
The victim leaps to his feet and runs to the front of the bar, as other patrons start realizing something's wrong. The attacker runs to the back of the bar and then out the back door.
Several patrons are right on his heels.
"Normally the bystanders are running the other way, but in this particular incident the bystanders took aggressive action and helped us get the guy," Chitwood said.
A short time later the victim stumbles into the hallway, and sits on a bench. One man takes off his shirt and presses it to the victim's throat, trying to stop the bleeding. Another emerges from a side room with a towel to bandage the victim's neck.
"His neck was just slashed, you could see where it was cut at, you could see the blood coming down his T-shirt," said witness Richard Blye.
The victim was rushed to the hospital in serious condition.
The suspect has been identified as 24 year old Julius Wilcox of Clifton Heights. The bar patrons say they had never seen him before.
Police say he used a rigging knife in the attack with a very sharp, seriated edge.
Despite the fact that he was armed and had just attacked a total stranger, regulars at the bar say it's not surprising that people ran after him.
"We're all family around here. We try to take care of each other, watch each other's backs, you know what I mean?" said Blye.
The police say this appears to be a completely random attack and the victim claims he had never seen Wilcox before.
Wilcox is facing multiple charges tonight, including attempted murder and aggravated assault, and he's being held on $750,000 cash bail.