Laws on "citizen's arrest" vary by jurisdiction. In my state, the law actually reads:
"A peace officer or any other citizen may arrest without warrant for an offense committed in his presence if the offense is a felony or breach of the peace, or to prevent the consequence of theft."
In other words, for a felony, there is no difference between the arrest powers of a peace officer or a private citizen. Likewise for misdemeanors that disturb the peace. Likewise for shoplifting. Only a peace officer, however, may arrest for other misdemeanors (traffic, parading without a permit, small-time vandalism, etc.).
We also have the following law:
"A person is justified in using deadly force against another to protect land or tangible, movable property: (2) when and to the degree he reasonably believes the deadly force is immediately necessary: (A) to prevent the other's imminent commission of arson, burglary, robbery, aggravated robbery, theft during the nighttime, or criminal mischief during the nighttime..."
In other words, if you're up to no good after dark, you're dead.
Try Google for: (your state)+arrest+citizen or some such. Or ask the next cop you see.