Not if they are in your house uninvited and you fear them to be a threat.
..Declaring that a person has no duty to retreat and has the right to stand his or her ground and the force is necessary to prevent death, great bodily harm or the commission of a forcible felony....THE persons residing in or visiting this state have a right to remain unmolested in ttheir homes or vehicles...
The person is presumed to have held a reasonable fear of immeninet peril.....The person against whom the defensive force was used was in the process of unlawfully and forcefully entering or had unlawfully and forcibly entered into a dwelling, residence or occupied vehicle.
Even if they are back to you, but still in your "castle" you have reasonable right to assume they have entered with the intent and capibility to do harm and so long as you can say you had fear, you can shoot to kill!
FL and TX Castle Doctorines are very similar, and in some cases IDENTICAL....Look up the case of Joe Horn, he shot and killed two intruders ATTEMPTING to enter a dwelling. When he shot them, he went out into the yard, yelled "HEY HEY YOURE DEAD", and shot them dead, unarmed and in the back in his front yard. He was NOT charged or arrested, the police department citing the Castle Doctorine.