Police believe a woman missing from her home in Kilmarnock for over a week may have come to harm.
Emma Faulds was last seen at about 21:10 on Sunday 28 April in the Monkton area of Ayrshire.
Police said it was “alarming” that the 39-year-old had not been in touch with friends and family, and that she had left behind her beloved pet dog.
Officers are carrying out a forensic examination of her car and searching properties in Monkton.
They said family and friends were “distraught” at not knowing where she is or what might have happened to her.
And they appealed for help from anyone who saw Ms Faulds or her car in the lead-up to her disappearance.
Police said she normally drives a blue BMW 1 Series M Sport with the distinctive registration number F5 EMA.
Her car has been removed by officers and is undergoing a full forensic examination.
Specialist officers have been searching areas and properties in the Monkton area, including two cars which are also being examined.
Ms Faulds is described as white, around 5ft 3in tall, with a slim, athletic build, long blonde hair, a pale complexion and blue eyes.
Detectives are also searching CCTV footage for any sightings of the missing youth worker or her car.
Det Ch Insp Martin Fergus from Police Scotland’s major investigations team said: “Emma is in constant contact with her family and friends and the fact that she has not been heard from is alarming.
“Emma also has a dog, a west highland terrier, and she would never leave it for any length of time without ensuring someone is able to look after it.
“We are liaising with Emma’s family and we now believe that she may have come to harm.”
He continued: “Emma’s car has been removed for examination and I am appealing to motorists, taxi drivers or members of the public who may have seen it being driven in the Monkton and Kilmarnock areas late Sunday night into Monday morning.
“I would ask people with dashcams to check their footage as they may have captured the car and not realise its significance. You may have noticed the registration number but thought nothing of it at the time, but now where and when you saw it could be vital.”
He added: “Emma is a sociable outgoing person who enjoys seeing her family and friends.
“They are distraught at not knowing where she is or what may have happened to her.
“I would appeal to anyone who may have information or knowledge as to her whereabouts to contact us.
“If you saw Emma a few days before she was reported missing, you may have information which could assist us so please do contact us, did you see her with anyone, did you speak her, any small piece of information could be highly significant.”