Three men in masks entered a bank to commit an armed robbery. A bank guard quickly pulled his gun and told the men to stand down. One of the robbers began to put his hand in his pocket, which the guard believed indicated that the robber was going for a gun. The guard promptly shot the robber dead. The police entered at that moment and arrested the other two robbers. Both men were arrested for robbery and for the murder of the third robber. The prosecution claimed that this was allowed under the felony murder rule. What will be the most likely outcome of the murder charges against the two robbers?