A- No, they are not. However, they can charge you with an offence like police, this is known as a private prosecution. They typically work mostly in civil matters.
They are permitted to contact you, follow you and keep you under surveillance. You cannot state they are “harassing you”. You can ask them why they are contacting you.
A- Stalking is illegal, whereas investigations are legal and defined in legislation.
A- You are or have had involvement in a civil or criminal matter. They are investigating and collecting evidence.
Often law firms will collect information to assist in child custody cases.
A- Due to the over work load, and lack of expertise in the state police organisations, private investigators typically have skills sets that fill the gaps., and or specialize in civil cases and often work with law firms. Also they catch people involved in infidality typically called “cheaters”.They being plain clothes work by using surviellence, obtaining information from their surroundings.
A- Under the Surviellence Devices Act 1999 (Victoria) section 6-8 it is illegal for anyone who does not have a warrant to use a device to determine the whereabouts of another person without their express or implied consent.
A- If the investigator is a private body guard and working in a capacity in which they are permitted to carried by the state police authourity such as an armed body guard.