The man, who is 40 and from St Leonards-on-Sea, was arrested on Thursday 25 November. Officers have been granted extra time to question him whilst a 53 year old man from Hastings, who was arrested in connection with the investigation on Friday 26 November, has now been released without charge.
Mother of two Alexandra Morgan was last seen at a petrol station near Cranbrook at 7.20am on Sunday 14 November 2021 and has not been in contact with her family since.
Her disappearance is being treated as suspicious and a potential murder.
Investigators remain keen to hear from anyone who may have information which can assist with their enquiries and have released a photo of her white Mini Cooper, which has a black roof and the registration number MF55 YHM.
They have established that, on Sunday 14 and Monday 15 November, the vehicle made journeys between her home and towards the Hastings area.
Kent Police officers, with support of Sussex Police are carrying out searches at four locations in the Hastings and St Leonards-on-Sea area, as part of their work to locate Alexandra.
Residents can expect to see a heightened police presence in the area as enquiries continue.
Det Ch Insp Neil Kimber, of the Kent and Essex Serious Crime Directorate, said: ‘It is completely out of character for Alexandra not to contact her family and we are now treating this case as a potential murder.
‘While we continue our investigation, I would urge anyone who may have seen Alexandra or her white Mini Cooper with a black roof to contact us.
‘If you think you may have seen Alexandra or something suspicious but are not sure, please do not hesitate to call and let us know.’
Anyone who has seen Alexandra or her car is urged to contact Kent Police on 101 quoting reference number 18-0280.
If you have other information, CCTV or dashcam footage that may be able to assist our officers, please upload to the Major Incident Public Portal via this link: https://mipp.police.uk/operation/4601020121F20-PO1
You can also contact Crimestoppers anonymously on 0800 555111, or by using the anonymous online form on their website.