Bulawayo police raided the offices of the National Youth Development Trust on Wednesday, two days after arresting two youths from the organization for allegedly possessing voter registration receipts.
Initially 40 people were detained on Monday but were later released, leaving Brilliant Goboza and Ray Ncube.
Zimbabwe Lawyers for Human Rights information officer, Kumbirai Mafunda, said the two were released on Wednesday after their lawyer, Charles Moyo, successfully challenged and convinced the prosecutor that they had not committed a crime, resulting in them being freed before going to court.
Mafunda said during the raid on Wednesday police searched the group's offices looking for voter registration certificates or material which 'negatively affected the state'.
There were no arrests this time around, but the police are said to have confiscated some documents, including the organization's workshop schedule and transport reimbursement details of its members.
Mafunda said civil society is 'under siege' as the police intensify their crackdown against activists ahead of elections.
He said ZimRights offices in Harare, Chinhoyi, Gwanda, Bulawayo have been raided in recent weeks and several people have been arrested with charges linked to voter registration.
There are currently four people, including Leo Chamahwinya (deputy programs manager for ZimRights) still in detention, facing similar charges of undertaking an "illegal" voter registration exercise ahead of the forthcoming polls.