My client has disclosed to me that he is secretly a masked vigilante in a major metropolitan city in the state of New Jersey, United States. Under this identity, he stops crimes in progress and turns the perpetrators over to the local police.1
We are trying to determine whether or not these actions are illegal (there are concerns of corruption in the city's police department, so we cannot rely on their tacit approval of his behavior). Furthermore, we would like to make sure that the individuals that my client turns over to the police will not be able to escape justice due to the manner in which they were captured, so we would like to know if there are any major limitations to what he can do that he should be aware of.
1 We will neither confirm nor deny rumors of other activities, including property damage, fighting other costumed individuals over personal vendettas, or driving an unregistered car without a license.