One who commits a tortious act is called a tortfeasor.
From the en.wikipedia.org
The standard is lower in other injury cases, so that a victim would have to prove that a tortfeasor had been negligent.
From the en.wikipedia.org
If someone has an accident then they have a statistical 8% chance of finding a tortfeasor responsible for their injury.
From the en.wikipedia.org
For a trespass to be actionable, the tortfeasor must voluntarily go to a specific location, but need not be aware that he entered the property of a particular person.
From the theargus.co.uk
If the deceased was statutorily bound to furnish maintenance to a third party, the tortfeasor shall also make compensation to such third party for any injury arising therefrom.
From the en.wikipedia.org
More examples
Tort-feasor: a party who has committed a tort
A tort (originally from the Old French, meaning "wrong", from medieval Latin tortum, meaning "wrong", past participle of torquere "to twist") is a wrong that involves a breach of a civil duty owed to someone else. ...
A person who commits a tort
A wrongdoer, a party guilty of a tort.
Person whose negligence caused the accident.
Person committing a tort; wrongdoer. The person who was at fault for the accident.
A person who commits a wrongful act of negligence which give rise to liability for damages.