It happened at the Sunoco gas station shop on Route 291 near Sellers Avenue.
"This guy is a real danger. We got to get this guy off the street," said Chief Stephen Edmiston with the Tinicum Township Police Department.
On Monday morning just before 9 a.m., police say a man entered the snack shop of the gas station, locked the door and turned off the lights.
"He made entry through an open glass enclosure where the clerk is and held the clerk at knifepoint," said Edmiston.
As customers kept coming to the door and finding it locked, he led the clerk to the office upstairs where he didn't just take the money.
"He assaulted him and like I said, this went on for 30 to 40 minutes in the store with people coming to the store pulling on the front door, the locked door as this was going on," said Edmiston.
A regular customer at a nearby business suspected something was terribly wrong and flagged down an officer.
"The officer went back, went in the business with him, heard what turned out to be the clerk crying out for help behind a locked door," Edmiston said.
The clerk had been tied and bound by his wrists and feet, the suspect nowhere to be found.
"We last have him at Rt. 291 and Sellers Ave in Ridley Township approximately 40 minutes after this occurred," said Edmiston.
A surveillance camera captured the suspect wearing a green Eagles sweatshirt nearby at the Red Roof Inn.
The gas owner is offering a $1,000 reward for anyone who can identify him.
"He had a distinct limp or gait if you will. He was walking not running. When he ran, he seemed to run fine, but when he's walking there's a distinct gait," said Edmiston.
Because of the brutality of the crime, police really want to get this guy off the streets fast. If you recognize him or otherwise know where he is, you are being asked to call the Tinicum Township Police Department.