A Chilean judge has ordered the arrest of nearly 100 former secret police and soldiers over rights abuses committed under General Augusto Pinochet, BBC reported.
The round-up is one of the biggest of its kind since the military leader's rule ended 18 years ago.
The 98 detentions are part of an probe into Operation Colombo, a 1975 plot to murder left-wing opponents of Pinochet.
More than 3,000 people were killed or "disappeared" during military rule in Chile between 1973 and 1990.
According to court documents, during Operation Colombo, Pinochet's feared secret police force, the Dina, seized 119 dissidents in July 1975 and killed them.
It is then said to have published news accounts claiming they had died in battles between leftist factions outside Chile.
The bodies of 42 of the dead were never found.
Most of the arrest orders issued on Monday were for former members of the Dina, others were for soldiers and civilians said to have collaborated with it.
Since the return to democracy in 1990, Chile has put dozens of soldiers, policemen and intelligence agents on trial for human rights abuses.
But correspondents say the number indicted at once on Monday is unusually high.
Among those listed is former Dina commander Manuel Contreras, who is already in jail in connection with other abuses.
Gen Pinochet - who died on 10 December 2006 - was accused of fraud as well as human rights abuses, but poor health meant he never faced trial.