suspicious — tending to cause or excite suspicion; questionable: suspicious behavior.
off guard — to keep safe from harm or danger; protect; watch over: to guard the ruler.
trustful — full of trust; free of distrust, suspicion, or the like; confiding: a trustful friend.
unsuspecting — to believe to be guilty, false, counterfeit, undesirable, defective, bad, etc., with little or no proof: to suspect a person of murder.
pre-warning — to give notice, advice, or intimation to (a person, group, etc.) of danger, impending evil, possible harm, or anything else unfavorable: They warned him of a plot against him. She was warned that her life was in danger.
