A surveillance image of the bank robber.

Suffolk County police are investigating a bank robbery in West Islip on Wednesday.

A man showed a teller a note demanding money at the TD Bank branch Montauk Highway at 12 p.m., police said. The teller complied and the robber fled on foot.

The suspect was described as a white man in his mid-20s, approximately 5-feet, 10-inches tall to 5-feet, 11-inches tall with a medium build. He was wearing a dark, hooded sweatshirt, dark-colored pants and dark sneakers with white laces.

Major Case Investigations Unit detectives are asking anyone with anyone with information on this incident to call anonymously to Crime Stoppers at 1-800-220-TIPS. All calls will be kept confidential.