Casablanca, Morocco ? Authorities have exhumed the remains of about 100 people killed during riots 24 years ago from a mass grave in Morocco and reburied them individually in a nearby lot.

Human-rights activists on Tuesday denounced the excavation, carried out Saturday in Casablanca without the presence of families and legal witnesses.

“It’s positive that authorities are exhuming mass graves. But why do it secretly at night?” asked Abdelkarim El Manouzi, a rights activist whose brother has been missing since 1972.

He and other critics said the exhumation might have damaged evidence for possible prosecution of perpetrators as well as for DNA tests to identify victims of riots June 20, 1981, sparked by food price increases.