Yes, it is possible for a landowner to be sued in a civil lawsuit by an injured trespasser committing vandalism on the property.
Frank W. Chen has been licensed to practice law in California since 1988. The information presented here is general in nature and is not intended, nor should be construed, as legal advice for a particular case. This Avvo.com posting does not create any attorney-client relationship with the author. For specific advice about your particular situation, please consult with your own attorney.
If they are injured is totally different from if they are injured by you. Probably not in the first, and depending on the detailed facts, very possibly yes on the second.
The above is general legal and business analysis. It is not "legal advise" but analysis, and different lawyers may analyse this matter differently, especially if there are additional facts not reflected in the question. I am not your attorney until retained by a written retainer agreement signed by both of us. I am only licensed in California. See also avvo.com terms and conditions item 9, incorporated as if it was reprinted here.
A person may be sued if they use illegal force on another person resulting in injury. You need to apply that law to your facts. Did you use illegal force on this person? Depends on what you did. If you shot someone who was spraypainting a wall, then yes. If you chased a person and they tripped, probably not. You are allowed to legally use non-lethal force to prevent your things from being vandalized or stolen. You are required to legally use the minimum force necessary to acomplish this goal. Non-lethal force is a bit a misnomer. It means that you cannot use force that is likely to result in death, or great bodily injury. Great bodily injury is defined as any injury that is more than transcient in nature. As a rule of thumb it means any injury that would require a doctor to treat it.