Criminal complaints have been filed in Haiti against former dictator Jean-Claude Duvalier, accusing him of crimes against humanity, including torture.
Mr Duvalier returned unexpectedly to Haiti on Sunday from exile in France.
He said he had "come to help" after a magnitude 7.0 earthquake a year ago which killed more than 250,000 people and left Port-au-Prince in ruins.
Michele Montas, a former spokeswoman for UN Secretary-General Ban Ki-moon, says she and three others who were imprisoned during Mr Duvalier's rule, filed the complaints with a prosecutor in Port-au-Prince on Wednesday.
On Tuesday, Mr Duvalier, 59, was briefly detained and charged by a prosecutor with corruption and embezzlement during his rule from 1971 to 1986.
Mr Duvalier arrived on the day that Haiti was supposed to hold a second round of elections to choose a successor to outgoing President Rene Preval.
"He will stay in Haiti forever, it's his country. And take part in politics. That's his right. A politician never dies," Mr Duvalier's lawyer Reynold Georges told AFP on Wednesday.
The BBC reports the vote has been postponed because of a dispute over which candidates should be on the ballot paper.
The first round of the election was held on 28 November amid widespread fraud and intimidation, according to international observers.
