Mark Charles Gell, 41, has not been seen since 10pm on Thursday June 16, and officers are "extremely concerned" for his welfare. He was last seen at his home address on Hambleton Terrace in York, and police believe he may now be in the Knavesmire area of York. Mark is around 6ft 3" tall, and of large build, with tattoos on both arms. He has short brown hair and a brown and ginger full beard. Police believe him to be wearing a blue or black sweatshirt, blue or black sports shorts, and black shoes. "Please call 999 for an immediate sighting or 101 with any other information which could help to locate Mark. Ref: 12220104853," officers said.