There are various conditions with which a Peace Officer (Metro or South African Police Services, etc) may arrest a person. It does however boil down to reasonable suspicion, whether a peace officer witnessed, or has a suspicion that a crime has been committed, the latter which can be due to a complaint laid at a police station. The arrest and detainment must however be lawful, in that there should have been reasonable suspicion, and that the police had to have followed the correct procedure - which can become complicated and is often neglected in statutory offences, such as possession.
When a person is arrested, according to the Constitution, he is entitled to be released on bail.
POLICE AND PROSECUTORIAL BAIL
The first avenue for bail is at a police station, after the person has been arrested and charged with an offence. This type of bail can only be given for minor offences, such as drunk driving, shoplifting, possession of dagga, common assault, etc.
Offences which are slightly more serious, but which are still considered minor, bail can still be applied for at a police station, a prosecutor on standby will however have to be contacted to secure a person's release on bail.
The amount granted at a police station various from area to area, as the prevalence of the offence and circumstances of the person arrested will be taken into consideration.
It is however suggested that an attorney be present when the person is being interviewed by the police after being arrested. This is often a crucial stage in the process, in that a person may inadvertently say the wrong thing and otherwise incriminate him or herself.
If a person is arrested for a more serious offence, or if the person has a previous criminal record or already has pending criminal matters in the courts, bail can not be granted at a police station. Bail will need to be applied for in a court. This procedure can be complex, and the success of bail being granted will depend on a variety of factors.
The law however dictates that a person must be brought before a court within 48 hours of being arrested. If this is not done, the person may have a claim against the Minister of Police for unlawful detainment.