Police have released a further CCTV image of missing Bradley man Bernard Hallas.
It captures the 84-year-old on a bus just hours before his disappearance on 18 December.
Detective Inspector Phil Benson of Huddersfield CID said: "The CCTV shows Mr Hallas leaving the bus at 8:38pm in Huddersfield Bus Station.
"His last sighting was at High Street at 10:41pm where he was seen heading towards Ramsden Street.
"We have therefore issued this image in the hope that it will encourage further people to come forward who may have seen him.
"Christmas day will mark a week since his disappearance and we are clearly concerned with each day that passes.
"He is an elderly man who requires medication and I would call on local people to come forward with any information, no matter how small or relevant they may think it is.
"Numerous searches have been undertaken by officers and our enquiries are ongoing across the area.
"Mr Hallas is described as white, around 5'5" tall, clean shaven, frail and with whispy grey hair. He was wearing blue check pyjamas, a brown sheepskin coat, a brown hat and black shoes.
"He is friendly man and I would ask that if you see him, please take him somewhere warm and phone the police.
"Likewise, if you know of his current location or have any information which could assist us in our enquiries, please contact 999 immediately."