Who said "Fear is the greatest weapon."?

This quote is attributed to Justice Wargrave.

Fear is the greatest weapon. - Justice Wargrave

"Fear is the greatest weapon."

Justice Wargrave Fear

Character in And Then There Were None

Buy "And Then There Were None" on Amazon

"Murder is justified when the victim deserves it."

"The guilty cannot hide forever."

"Justice must be served."

"Every man and woman is alone."

"Face your fears with courage."

"You can't live your life in fear."

"Snakes. Why'd it have to be snakes?"

"Fear is just another obstacle to overcome."