Detectives are examining a 41-ton Spanish registered articulated lorry in which an alleged illegal asylum seeker died.
The body was found when police stopped the lorry
A post-mortem examination on the man, who was found between metal containers of paint, believed to be an Iraqi Kurd, is to be conducted at the Bournemouth mortuary on Tuesday.
Two men other men who were also discovered inside the container and also thought to be Iraqi Kurds, are being questioned by police.
They were arrested after the vehicle was stopped by police on the Fleetsbridge flyover in Poole, Dorset, shortly before 0840 BST on Sunday.
Inspector Shaun Cronin, of the Ferndown Road policing unit, is still appealing for anyone who may have seen the blue and white container
lorry stopped on the westbound carriageway of the A3049 Dorset Way, to come forward.
He said: "Nothing has so far been found and we are investigating if there were only three alleged illegal immigrants in the lorry carrying containers of paint and vehicle parts - the two who were arrested and the one who was found dead between the paint containers in the lorry.
"Thanks to the media's help, we have traced the male motorist who first raised the alarm via the ambulance service when he saw the lorry stopped on the dual carriageway at Oakdale with its rear doors open and people getting out on Sunday."
It is believed the containers crushed the man
The lorry driver, a Spanish man in his 40s, is also still being questioned over motoring offences and immigration matters.
Dorset Police is working with the immigration service.
Police think the lorry gained entry to the UK via Portsmouth Docks early on Sunday, after crossing from Le Havre in France.
Insp Cronin, added: "I would urge the public of Canford Heath, Oakdale and Fleetsbridge to continue to be vigilant and to report any suspicious activity while police establish exactly how many people were in the lorry."