Washington State law...
RCW 9A.16.020 - Use of force — When lawful.
The use, attempt, or offer to use force upon or toward the person of another is not unlawful in the following cases:
(3) Whenever used by a party about to be injured, or by another lawfully aiding him or her, in preventing or attempting to prevent an offense against his or her person, or a malicious trespass, or other malicious interference with real or personal property lawfully in his or her possession, in case the force is not more than is necessary;
Seems to me that use of force was lawful.... and (emphasis added)
RCW 9A.16.050 - Homicide — By other person — When justifiable.
Homicide is also justifiable when committed either:
(1) In the lawful defense of the slayer, or his or her husband, wife, parent, child, brother, or sister, or of any other person in his or her presence or company, when there is reasonable ground to apprehend a design on the part of the person slain to commit a felony or to do some great personal injury to the slayer or to any such person, and there is imminent danger of such design being accomplished; or
(2) In the actual resistance of an attempt to commit a felony upon the slayer, in his or her presence, or upon or in a dwelling, or other place of abode, in which he or she is.
And finally....
RCW 9A.56.065 Theft of motor vehicle.
(1) A person is guilty of theft of a motor vehicle if he or she commits theft of a motor vehicle.
(2) Theft of a motor vehicle is a class B felony.
I'm not sure why the victim was charged, or under what law he could be convicted.
