Vancouver police are searching for a man who robbed a Chase Bank branch and left an authentic-looking explosive device at the scene Saturday.The robbery occurred at 11:52 a.m. at the Chase Bank at 13215 S.E. Mill Plain Blvd. in east Vancouver. Police said a man entered the bank carrying a pink bag and presented a demand note, indicating he was heavily armed, had a bomb and wanted cash.He was given an undisclosed amount of cash, police said, and fled on foot. He was last seen running west from 131st Avenue and Southeast Fifth Street, witnesses said. A police K9 unit could not locate the man.As he left, he dropped the pink bag he was carrying. Because it might have contained a bomb, police evacuated and sealed off the bank and nearby parking lot. The Metro Explosives Disposal Unit responded and “rendered the device safe,” said Vancouver Sgt. Wayne Reynolds. Reynolds said he was not sure if the device was a real bomb or a fake, but the FBI is conducting a follow-up investigation.At first, witnesses described the robber as a Hispanic-looking male in his 20s, although additional witnesses have said he was a “light-skinned black male or more likely Filipino,” police said. The man has average height and weight. He was described as having dark hair, although one witness suggested he may have been wearing a wig.Surveillance photos show the robber wearing loose-fitting blue jeans and a dark windbreaker-type jacket with three white stripes down the sleeves. The bank robbery is the second in three days — police unsuccessfully combed the Stockford Village area of Hazel Dell late Thursday morning while searching for a dirty-looking man who robbed an Umpqua Bank branch. He has not been arrested.The robber in that case was described as a balding white male, perhaps 50 to 55 years old, with curly brown hair on the sides, wearing a brown jacket and blue jeans. He was described as approximately 5 foot 4 inches tall with an average build.