SOUTH PHILADELPHIA (WPVI) -- The search is on for two suspects who pulled a knife on a man, and viciously beat him, during a robbery in South Philadelphia.The attack happened in the 400 block of Dickinson Street around 3:15 a.m. on August 15.Police say two unknown white males approached the victim from behind and attacked.Investigators say they pulled a knife on the victim and demanded his valuables.Surveillance video shows the suspects throwing the victim to the ground. One man is seen holding the knife while the other kicks the victim.The suspects took the man's wallet, which contained credit cards and just $2 in cash, then fled south on 5th Street toward Tasker.Anyone with information about these suspects is asked to contact Philadelphia police.------