Direct identifies a specific act against a specific target and is delivered in a straightforward, clear, and explicit manner
Indirect is vague, unclear, and ambiguous violence is implied, but the threat is phrased tentatively and suggests that a violent act could occur, not that it will occur.
Veiled strongly implies but does not explicitly threaten violence.
Conditional is often seen in extortion cases. It warns that a violent act will happen unless certain demands or terms are met.