The lawyer for the victim's family said some of the migrants held in the prison in Archidona near Malaga in southern Spain had been transferred to other centres around the country, while others were deported.
Amanda Romero added that among those evacuated were potential witnesses to the circumstances surrounding the death of Mohamed Bouderbala, 36, who was found hanging on December 29th.
In a statement, the interior ministry said the "572 migrants, all of them Algerian, who were in this Malaga centre since the end of November have been gradually transferred."
It did not say where they were taken and a spokeswoman refused to comment further.
The use of the new jail as a so-called CIE, a centre where migrants are held pending asylum claims or deportation after they arrive in Spain, drew sharp criticism by rights groups.
Spanish law states that CIEs must not "be penitentiary in nature."
But the interior ministry said it had decided to use the jail due to a lack of space at other detention centres, as the number of migrant arrivals in Spain more than doubled last year on 2016, setting a new record at around
"The interior ministry has always preferred this solution to building temporary camps, as has been done in other countries, which don't guarantee the minimum worthy living conditions," it said.
Romero said she thought the evacuation had been enacted in direct response to the controversy caused by the death of Bouderbala, who according to an autopsy hanged himself with a sheet.
His brother Ahmed told reporters last week he spoke to Mohamed the morning before he was found dead, and that he was not suicidal.
But a judge dropped a probe into the death just a few days after the incident, prompting Romero to question "the speed" in which the case was closed and appealing the decision.
On Wednesday, she said she did not as yet know whether potential witnesses inside the centre, who have "versions that could contradict official ones," were sent back to Algeria or remained in Spain in other centres.