Like how the killers knew where to leave the bottle of blood in the first place.

"The killer knows something about drugs and how to use them?"

If the killers knew they were watched, it might save the second girl.

The killers knew that no one but them should have the access numbers for this level.

The killer she told me about knows who I am.

He's more powerful than anyone, and even killers know that.

Now if that were true, then his killer would almost certainly have known about the money.

It seemed likely that the killer didn't know the guard was dead.

Maybe because the killer knew that place well enough to set up an inside job.

What else did the trained killer know how to do?