Police searching for missing Robert Hutchinson have released new images of his car.
It's four weeks since Robert, 57, was last seen leaving his home in Corporation Road in Hendon, Sunderland. He was in his car.
The blue coloured Nissan Micra was later recovered at the end of Stewart Street, just off Chester Road.
"Someone must recognise this car - did you see it being driven around the area at any time after 6.20pm on Monday, June 23? Did you see it being left at Stewart Street, which is just off busy Chester Road?
"Even the smallest detail can be vital in piecing together Robert's movements and I'd urge anyone who thinks they have information which may help us in our enquiries - no matter how insignificant they feel it may be - to contact us.
"Calls can be taken in the strictest of confidence. This is an incredibly difficult time for the family and the most important thing is finding out what has happened to Robert for the sake of his family and friends.
"I believe there are people within the community who will have information that will assist the enquiry and I would urge those people to come forward."
Police are appealing for information four weeks after Robert Hutchinson was last seen.
The 57-year-old went missing from his home in Corporation Road in Hendon, Sunderland.
He left in his car - a blue Nissan Micra - which was later recovered at the end of Stewart Street, just off Chester Road.
Last week, two men were questioned on suspicion of murder and have been released on police bail pending further enquiries.
"Robert was a dedicated family man and a doting grandfather, he visited his grandson most days as well as spending time visiting other friends and family.
"This is an exceptionally difficult time for his family who are desperate to know what has happened to him. It is crucial people who have information now come forward.
"Someone must have information, and I would ask those people to think about how they would feel if this was their family member - a grandson is missing his grandfather, a son and daughter are missing their father.
"I believe there are people within the community who will have information that will assist the enquiry and I would urge those people to come forward.
"We don't know what happened to Robert or where he is now. How did his vehicle come to be in Stewart Street?
"We know Robert left his home on Monday, June 23, at 6.20pm in his car, the car was later found parked at the end of Stewart Street, just off Chester Road. If anyone saw him, either leaving his home or in Stewart Street or saw the car or the car being parked in Stewart Street, we want to hear from them."
Police continue to appeal for witnesses after disappearance of Sunderland grandfather Robert Hutchinson, on his 57th birthday.
Robert Hutchinson was last seen on June 23, in Hendon and was reported missing on June 26.
Yesterday, three men were arrested in connection with his disappearance.
"Today is Robert's 57th birthday, and our thoughts are with his family at what is an exceptionally difficult time for them. They need answers as to what has happened.
"Our enquiries to find Robert are on-going, we are searching a number of areas and carrying out a number of enquiries. We believe there will be members of the community who have information and we need those people to come forward and speak to us. I would like to reiterate that we will treat information in the strictest of confidence."
"We would ask those who know what has happened to think how they would feel if this was one of their family members. No matter how small the information is it could prove to be fundamental in our enquiries."
– Detective Chief Inspector Nicola Musgrove, of Northumbria Police Major Crime Team
Anyone with information is asked to contact Northumbria Police on 101.
A 59-year-old man has been released with no further action.
The grandfather-of-one has not been seen since June 23 in Hendon.
This morning, a 55-year-old man was arrested on suspicion of murder and two men, aged 59 and 39, were arrested on suspicion of assisting an offender.
Enquiries have been carried out to trace him, including viewing CCTV, carrying out house to house enquiries and speaking to people who knew him.
Chief Inspector Jerry Pearson, of Sunderland Area Command, said: "This is a fast moving investigation that has recently seen a number of significant developments that have led to three men being arrested this morning.
"Robert's family have been updated on this development and are understandably incredibly distraught by this. It is crucial we now find out the full circumstances of what has happened and we are continuing to ask for witnesses to come forward.
"If anyone has any information they think may help, no matter how small it may be, we want them to contact us. We will treat any information in the strictest of confidence and respect the anonymity of callers if this is a concern."
Anyone with information should contact Northumbria Police on 101 ext 69191 quoting reference 410 260614 or Crimestoppers anonymously on 0800 555 111.
Chief Inspector Jerry Pearson, from Northumbria Police, is urging anyone who knows the whereabouts of missing Robert Hutchinson to contact them. The 56 year old, from Sunderland, hasn't been seen since the 23rd of June.
The family of a man who's been missing for more than 2 weeks have made an emotional appeal for him to get in touch. 56 year old Robert Hutchinson was last seen on the 23rd of June in the Hendon area of Sunderland. His daughter, Paula Hutchinson, and son, Gavin Newton, say they want him home.