A Hungarian court is due to rule in a trial of 14 men accused over the death of 71 migrants who suffocated in a sealed lorry in August 2015.
Police found their decomposing bodies in the lorry, registered in Hungary and abandoned near an Austrian village.
The discovery provoked global outrage. At the time central Europe faced a huge influx of migrants, many of them fleeing Syria and other conflict zones.
Most of the alleged gang members are Bulgarians. Four face murder charges.
The accused, on trial in the city of Kecskemet, all denied belonging to a criminal people-smuggling organisation and expressed remorse.
What happened and who were the victims?
The victims came from Iraq, Afghanistan, Syria and Iran. They included eight women and four children; the other 59 were men. All but one were identified.
29 from Iraq, mainly Iraqi Kurdistan including towns of Dohuk and Zakho
21 from Afghanistan
15 from Syria, including from town of Qamishly
1 still unidentified
Crammed into the back of a small Volvo meat lorry, with standing room only, the 71 victims are believed to have suffocated less than three hours after it set off.
They died on a scorching hot day while the lorry was still in Hungary. It was found near Parndorf, just across the border in Austria.
The lorry, emblazoned with pictures of sausages and a chicken’s head, had been sealed airtight.
What are the charges?
According to the prosecution, the smugglers knew that the migrants squeezed into the back were going to die, and they ignored the sound of them banging on the sealed interior, as the oxygen ran out.
Prosecutors want life imprisonment with no chance of parole for three of the four accused of murder.
The alleged ringleader is Samsoor Lahoo, a 31-year-old Afghan. The evidence produced against him includes a phone-tap recording in which he allegedly orders the driver to keep going despite the victims’ cries for help.
Three of the 14 defendants are still at large and are being tried in absentia. Nine Bulgarians, Mr Lahoo and a Lebanese national are in court.
Besides the murder charges levelled against four, all the defendants are charged with human trafficking and torture.
Prosecutors say the group was charging migrants up to €3,500 (£3,100; $4,100) per head and had planned two more smuggling journeys for 27 August – the day after the bodies were found.
What was the reaction?
The tragedy fuelled an outpouring of sympathy for refugees and migrants, and was a catalyst in the decision in August 2015 to open borders and allow them to head on towards Germany. In 2015-2016 about one million were allowed to stay in Germany – a highly controversial decision.
But as the crisis continued into 2016 Austria’s then foreign minister and now Chancellor, Sebastian Kurz, played a key role in shutting down the Balkan route used by migrants.
Barriers went up, including a formidable razor-wire fence on Hungary’s southern border, completed in April 2017.