Joseph smith had a smuggled pistol at carthage Jail.

He received it from Elder Cyrus Wheelock when he came to visit them at carthage jail. When Joseph's enemies broke into the jail and attacked joseph and his associates, Hyrum was shot in the face and died almost instantly. After taking a moment to mourn for his fallen brother, Joseph pulled out the smuggled six shooter peperbox pistol and used it to shoot three of the mob, two of whom reportedly later died. This information is from a letter written by John Taylor, who was there at Carthage Jail at the time

Also, while waiting at carthage jail, joseph and the others ordered some wine to be brought up to them. Taylor explained in his letter that this wine was not meant to be taken for sacrament purposes, but rather, it was meant to lift their spirits and cheer them up. They all felt rather depressed because of the situation they were in, and sought a form of escapism for a short time.

The reason why Joseph smith was taken to the jail in Carthage was because he had ordered the destruction of a local printng press in Nauvoo after it published a single editorial issue exposing Joseph's corruptive power as Mayor of Navuoo and his secret practising of polgamy. He allegedly had as many as 30 wives, if not more.

Further more, the reasoning for Smith's final words, "OH, lORD, MY GOD" was because he was attempting to give a masonic distress call. What he really was trying to say was, "Oh, lord, my God, is there no help for the widow's son?". In his final moments, Joseph hoped that there were fellow masons outside who would hear his distress call and come to his aid, but, unfortunately for him, they didn't.

He was shot and killed in cold blood before he could even finish giving the distress call.