A Greek fruit exporter and three foremen arrested over a near-deadly shooting attack against migrant labourers were placed in pre-trial detention on Monday, police said.
The four men had been arrested in the Peloponnese peninsula last week after the incident in which around 30 strawberry pickers demanding long-overdue pay were wounded, some of them seriously.
The Supreme Court prosecutor on Monday said the victims would be granted special protection to prevent their deportation so they can testify.
The migrants, mainly from Bangladesh, will be granted human trafficking victim status, a justice source said.
The attack occurred in the village of Manolada in the west of the peninsula, one of the main areas of strawberry production in Greece.
The three foremen are accused of firing at a crowd of 200 migrants who had gathered to demand back pay which in some cases stretched to six months.
The three defendants said they had acted in self-defence as the crowd had become hostile.
The 57-year-old farm and company owner was also arrested as a "moral instigator" of the shootings.
The company owner, who denies involvement, has complained of heart trouble and was hospitalised under guard in the neighbouring town of Pyrgos.
One of the shooting suspects was involved in another attack last year against an Egyptian labourer who was dragged from a car and injured in a similar dispute over pay.
The government condemned the shooting but unions noted that the incident was only the latest in a long history of abuse of migrant workers in Greece.
In 2008, Manolada was the focal point of a rare strike by hundreds of migrant workers against near-slavery conditions in the fields.
Hundreds of seasonal workers, most of them foreign, are employed in local farms for meagre wages, living in shacks and forced to pay rent to their employers.
They work in greenhouses in temperatures up to 40 degrees Celsius (104 Fahrenheit) for a salary of around 22 euros ($29) a day.
The treatment of migrants in Greece has long been criticised by domestic and international rights groups, to little avail.