In a unanimous panel opinion, the Arizona Court of Appeals, Division 1, ruled that there can be no offense of "attempted felony murder" under Arizona law. The Court explained its reasoning in State v. Moore, which depends on the legal defininition of felony murder. Felony murder is an offense that occurs when a person is killed during the commission of a felony offense. The death of the person need not have been intended by the defendant -- the only intent that is required is the intent to commit the felony offense. In effect, the intent to commit murder is supplied by the felony murder statute.
In contrast, the offense of attempt does require an intent -- the intent to commit another offense, even though that offense does not actually occur. The Moore Court looked at these two offenses together, and reasoned that a charge of "attempted felony murder" would require the State to prove that the defendant intended to cause an unintended death. In other words, the charge would require proof that a person intended an unintended consequence -- a logical absurdity. Accordingly, the Court ruled that the offense of "attempted felony murder" does not exist in Arizona.
The full opinion can be found at: http://www.cofad1.state.az.us/opinionfiles/CR/CR07-0475.pdf.