Was julius caesar death justified in the play

If "the play" you're talking about is Julius Caesar by William Shakespeare, then this question is actually a form of opinion. There is no right or wrong in the actual, factual basis of the topic because some believe it was justified that the conspirators were doing what they thought was best for Rome, and some believe Brutus never should have joined them because he was Caesar's closest friend. In matters of betrayal, you have to read the play yourself and answer this.