Thames Valley Police have renewed an appeal for information, seven weeks after a man went missing from Kidlington.
Derek Brant was last seen on the 24 July near St Anne's Annexe in Summertown.
The 63-year-old was wearing a navy/black coloured polo shirt, black cargo trousers and a fluorescent jacket at the time.
Officers said he is known to spend time in Kidlington and Summertown and sometimes helps the local community with litter picking.
Superintendent Emma Garside, Thames Valley Police
Detective Chief Inspector Kelly Glister said: "I would like to take this opportunity to thank everyone who has come forward so far with information in order to help us find Derek.
"Despite extensive enquiries and searches, the last sighting of Derek is still from 24 July.
"Although it has now been a number of weeks since Derek went missing, if anyone thinks they have seen him, or has any information that they think could be important then please get in touch by calling us on 101 and quoting the reference 43210328398.
"I'd also ask the community to please regularly check cars, sheds, outhouses and gardens in case Derek has sought shelter."