A 30-year-old man was robbed at knife-point while walking home from visiting his mother's grave in Lancashire.
The man was on a path off Watkin Lane, Lostock Hall, at about 1430 BST on Monday when he was approached by four men.
They engaged the victim in conversation before one of the men produced a knife and demanded money.
They took cash out of his pockets and pushed him to the ground, police said.
The attackers are described as being in their 20s and one was wearing a dark blue hooded top.
The man who threatened the victim with the knife is described as having very short, almost shaven dark hair, of very slim build and he had some teeth missing.
Det Sgt Jon Cass appealed for witnesses to contact Lancashire Police.
He added: "Although the victim was not physically hurt during this robbery, he was clearly very shaken by the experience."