Premeditation May Be Inferred Based on Circumstantial Evidence
Premeditation may be inferred based on circumstantial evidence such as:
 the nature of the weapon used;
 the presence or absence of adequate provocation;
 previous difficulties between the parties;
 the manner in which the homicide was committed;
 the nature and manner of the wounds inflicted;
 It must exist for such time before the homicide as will enable the accused to be conscious of the nature of the deed he is about to commit and;
 the probable result to flow from it insofar as the life of the victim is concerned. Jackson v. State, 575 So. 2d 181, 186 (Fla. 1991) (quoting Sireci v. State, 399 So. 2d 964, 967 (Fla. 1981)).
To prove premeditation by circumstantial evidence, "the evidence relied upon by the State must be inconsistent with every other reasonable inference that could be drawn." Norton, 709 So. 2d at 92 (quoting Holton v. State, 573 So. 2d 284, 289 (Fla. 1990)).
In State v. Law, 559 So. 2d 187, 188 (Fla. 1989), the Court further elaborated on the standard in circumstantial evidence cases as follows:
It is the trial judge's proper task to review the evidence to determine the presence or absence of competent evidence from which the jury could infer guilt to the exclusion of all other inferences.
That view of the evidence must be taken in the light most favorable to the state.
The state is not required to "rebut conclusively every possible variation" of events which could be inferred from the evidence, but only to introduce competent evidence which is inconsistent with the defendant's theory of events.
Once that threshold burden is met, it becomes the jury's duty to determine whether the evidence is sufficient to exclude every reasonable hypothesis of innocence beyond a reasonable doubt. Id. at 189.
Premeditation is "more than a mere intent to kill; it is a fully formed conscious purpose to kill.
This purpose may be formed a moment before the act but must exist for a sufficient length of time to permit reflection as to the nature of the act to be committed and the probable result of that act." Norton v. State, 709 So. 2d 87, 92 (Fla. 1997) (quoting Coolen v. State, 696 So. 2d 738, 741 (Fla. 1997)).