The most recent incident happened around 5:30 p.m. Wednesday at National Fuel on Route 130 at Tenby Chase Drive in Delran, New Jersey.
Parshotem Singh is the manager here and came face to face with the suspect.
He says the suspect knocked on the door of the gas station office.
Singh thought he was a customer who needed car maintenance and let him in. That's when the suspect allegedly pulled out a knife and demanded money.
"He says 'Come here and give me money,' I said 'Why?' and he said 'I have a knife,'" said Singh.
Singh said the man punched him repeatedly then grabbed an envelope containing $1,000 in cash and ran off.
Police suspect he was attacked and robbed by Johnson.
When Singh saw a photo of Johnson posted on 6abc.com, he told Action News that he's sure it's the same man he came face to face with yesterday.
"Yea, it looked like him," said Singh.
Johnson is wanted for the Feb. 11th murder of 46-year-old Bal Krishna Karki - an immigrant from Nepal
Karki was working at the Lukoil gas station on Route 130 and Charleston Road in Willingboro, when he was shot and killed during a robbery.
Johnson is also wanted for robbing a Willingboro convenience store on Feb. 12th.
The suspect is described as 5'9" tall and 265 pounds. Anyone with information about Johnson's whereabouts is asked to call Willingboro Township Police at (609) 877-2253.
Police say Johnson is considered armed and dangerous and if spotted, please call 9-1-1 immediately.