What’s a "Proxy Murder."

A proxy murder is a murder in which the murderer does so at the behest of another, acting as his or her proxy.
The archetypal example of this would be taking a contract out on someone else, in which a hit man commits the act of murder on a specified target for the client, e.g. in exchange for money; this would be a contract killing. Another example is a person who manipulates a lover into murdering for him or her. One reference would be Charles Manson who sent his family and followers to commit murders, which he himself was later sentenced for.
The person instigating a proxy murder may or may not be legally guilty of the crime of murder; this legal distinction varies by nation (and within the United States, by state). However, all jurisdictions recognize the criminal nature of the actions taken by the instigator, and they may be charged under any of a variety of statutes, including murder, conspiracy to commit murder, and/or accessory to murder.
Proxy murders may skew crime statistics, as the use of a proxy may conceal the true motives of the person.