Police are renewing appeals for information from members of the public who may have seen the burgundy red BMW owned by the man found seriously ill in Salisbury.
Officers are today releasing a picture of Sergei Skripal's burgundy red BMW 320D saloon - registration plate HD09 WAO - about which they appealed for information earlier this week.
Sergei, 66, and his daughter Yulia Skripal, 33, were found seriously ill on a bench in Salisbury town centre on Sunday, 4 March. Scientists determined this to be the result of a military grade nerve agent. Both Sergei and Yulia remain in a critical condition in hospital.
A Wiltshire Police officer - Detective Sergeant Nick Bailey, who was among those first to respond to the incident - was also taken ill and remains in a serious but stable condition in hospital.
Met Assistant Commissioner Neil Basu said: "We are learning more about Sergei and Yulia's movements but we need to be clearer around their exact movements on the morning of the incident.
"We believe that at around 9.15am on Sunday, 4 March, Sergei's car may have been in the areas of London Road, Churchill Way North and Wilton Road. Then at around 1.30pm it was seen being driven down Devizes Road, towards the town centre.
"We need to establish Sergei and Yulia's movements during the morning, before they headed to the town centre. Did you see this car, or what you believe was this car, on the day of the incident? We are particularly keen to hear from you if you saw the car before 1.30pm. If you have information, please call the police on 101."
Anyone who has images or footage that may assist the investigation is asked to upload them at the secure website http://www.ukpoliceimageappeal.co.uk
AC Basu continued: "In any investigation, the information we receive from the public can be crucial to helping the police build a picture of events and in this case the public response has been immense. Around 400 witnesses have already given statements, with hundreds more to be taken in the coming days.
"This is an extremely challenging and complex investigation and we currently have around 250 exceptionally experienced and dedicated specialist officers from the counter terrorism network working around the clock on this case.
"They are being supported by hundreds more officers from across the police family, as well as the military and other emergency services.
"To date, detectives have recovered 762 exhibits and are trawling through around 4,000 hours of CCTV. They are making good progress in what is a painstaking investigation that is likely to be ongoing for weeks, if not months."
Police have today released the following updated timeline of events (all times approximate):
14.40hrs on Saturday 3 March: Yulia arrives at Heathrow Airport on a flight from Russia.
09.15hrs on Sunday, 4 March: Sergei's car is seen in the area of London Road, Churchill Way North and Wilton Road.
13.30hrs: Sergei's car is seen being driven down Devizes Road, towards the town centre.
13:40hrs: Sergei and Yulia arrive in Sainsbury's upper level car park at the Maltings. At some time after this, they go to the Bishops Mill Pub in the town centre.
14.20hrs: They dine at Zizzi Restaurant.
15:35hrs: They leave Zizzi Restaurant.
16.15hrs: Emergency services receive a report from a member of the public and police arrive at the scene within minutes, where they find Sergei and Yulia extremely ill on a park bench near the restaurant.
As the investigation continues, the local community will continue to see a police presence at various sites across Salisbury, and also in Dorset where the military have been helping police remove a number of vehicles and items.
AC Basu explained: "Public Health England has advised that the risk to the public is low. I would like to reassure anyone who may be concerned by the continued presence of officers wearing specialist protective clothing that they are wearing this as a precaution and that it is not an indication of an increased risk."
Anyone with concerns regarding the ongoing police activity at these locations is encouraged to speak to any of the local officers or PCSOs at the locations, who will be happy to offer reassurance.
For the full advice from Public Health England, please see http://www.gov.uk/government/news/public-health-england-statement-regarding-events-in-salisbury