- Inspector Gregg: Somewhere out there at this moment, a murder is being contemplated, and all I can do is wait for death. I start at death, and I have to work my way back to life. And when I find life, I have to destroy it.
- Stella: Don't tell them anything, Mark, you were with me Saturday and Sunday.
- Doctor Steele: [to himself] That's why she's so worried. I have no alibi.
- Doctor Steele: Neurology... neurology... the results are beyond imagination. To penetrate man's mind intrigues me more and more.