@DudeManGuy
All these things are in the game. :T

@DudeManGuy
Not just any serial killer. Yoshikage uses a special spirit in JoJo called a Stand. He calls it Killer Queen.

It can make a bomb out of anything it touches: A 10 Yen, a door knob, a person.

A second bomb, suitably named Bomb #2: Sheer Heart Attack, which is launched from the top of its right hand. It’s pretty much the Energizer Bunny with a suicide bomber vest and it also never gets destroyed in its own explosions.

Later in the Kosaku Kawajiri arc, Killer Queen evolves and gains a third bomb: Bomb #3: Bites the Dust. It waits somewhere on a person (who can’t weild a Stand), then when a Stand User sees it, uses Bites the Dust to blow its opponent up. They logically die, but time is rewound to a point where they’re obviously alive.

Only Yoshikage can enable or disable Bites the Dust, and Killer Queen cannot fight while Bites the Dust is active hidden inside a normal person.

Up until a point, Yoshikage only ever used the first two bombs to kill without leaving a trace. Only a Stand can potentially leave no evidence for police to discover because a Stand is a spiritual entity, and the damage it can cause has the ability to be unseen by normal people. Of course, it varies between each Stand.