Extensive analysis of distinctive features on a Buk surface-to-air missile transporter, used to shoot down Malaysia Airlines flight MH17, shows the vehicle originated from a Russian armed forces division stationed outside the city of Kursk.
The Joint Investigation Team probing the destruction of the Boeing 777-200ER on 17 July 2014 has scrutinised characteristics of the vehicle and its movements, and concluded that it originated from the 53rd anti-aircraft missile brigade.
In an update to the MH17 criminal inquiry the team has detailed its examination of video footage and photographs which led to the finding.
Dutch national police criminal investigation department chief Wilbert Paulissen, speaking during the briefing, said he was "convinced" that the analysis – which needs to be legally sound – has proven the origin of the transporter.
Chief prosecutor Fred Westerbeke says that, while the criminal probe is "steadily progressing", it remains "large and complicated", and that the inquiry is currently unable to answer the crucial questions as to why MH17 was shot down and who was responsible.
Westerbeke points out that the determination of the origin of the transporter opens new avenues for the criminal probe.
"This observation raises questions, such as the question whether the brigade itself was actively involved in the downing of flight MH17," he says. "It is an important question which the [team] is still investigating."
Russian authorities have not reported to the team that a Buk missile transporter from the brigade was used in eastern Ukraine, from where the investigators have previously shown that the missile was fired.
Westerbeke says the team "no longer" wants to deal "exclusively" with Russian authorities in order to obtain information on the subject, and it is publicly opening its lines of inquiry to other individuals – even inviting personnel from the brigade itself, and their friends and family, to respond.
Paulissen states that the team is looking specifically for information on those responsible for the Buk's deployment on the day of the attack, what instructions were given, and by whom.
"We're convinced many people have this information available to them," he says.
Analysis of the transporter has identified several features of the vehicle, including centre-of-gravity markings, numbers, white spots, and characteristics including an opening on the side-skirt and a distinctive single spokeless wheel on the right side.
The examination has even involved computer-generated simulation of shadows to show that a vehicle in a particular photograph had the same specific combination of wheels.
All of these have helped build a "fingerprint" of the vehicle, says the inquiry, which uniquely matches one from the 53rd anti-aircraft missile brigade – which comprises three operational battalions – and not "any other" such transporter.
The inquiry says a convoy of about 50 assorted vehicles, including six Buk transporters, left the brigade's station at Kursk on 23 June, heading south.
Multiple videos and photographs supplied to the investigators have enabled the team to compare licence plates and location identifiers. The team states that the military vehicles were large and disruptive, and attracted attention, the reason why so many images have become available.
The convoy travelled a route through Stary Oskol, Alexeyevka, Rossosh and Millerovo over the course of 23-25 June 2014. Millerovo is some 430km from Kursk but just 25km from the Ukrainian border.
Previous analysis had already shown the missile transporter used to bring down MH17 was recorded multiple times on 17-18 July 2014 when it was transported in Ukraine on a red low-loader drawn by a white Volvo truck.
Investigators are also searching for more information on the missile itself, particularly an identification number on the missile casing, and handwritten numbers on the exhaust port retrieved from the MH17 crash site.
"We urgently appeal to everyone, anywhere in the world, who can give the [inquiry team] more information about [these markings]," says Australian federal police commander Jennifer Hurst, stressing that all informants will be treated with "the utmost confidentiality".