2. Under what circumstances can the ICAC officers arrest a person? Must they obtain a warrant of arrest beforehand?
A warrant of arrest is not required. The ICAC officers may arrest a person they reasonably suspect of being guilty of an offence under the Independent Commission Against Corruption Ordinance, the Prevention of Bribery Ordinance, or the Elections (Corrupt and Illegal Conduct) Ordinance. What constitutes reasonable suspicion in a particular case is to be judged on an objective basis with valid reasons.
Examples of these offences include: a civil servant accepted advantages without the Chief Executive's permission when performing an official duty, or staff of a private company released tendering information to bidders in return for some advantages and such information has assisted those bidders in securing a contract. If you want to view more examples concerning corruption, please visit the ICAC webpage.
The ICAC officers have a duty to explain to the person under arrest the reason for the arrest, and to inform the arrested person that he has a right to remain silent. Hence, the arrested person can choose not to answer any questions asked by the ICAC officers .
It should be noted that a person is not under arrest if that person is merely asked by the ICAC officers to assist in their investigation or to go to the ICAC Office. Unless the person is formally arrested, he is free to decide whether or not to go with the ICAC officers, and is free to leave at any stage.