"Possible Scenarios of Situational Offenders:

They can be family members, teachers, coaches, babysitters, and most juvenile offenders. Examples:
A grandfather that never abused his own children, but sexually molested his grandchildren.
A teacher that seduced a student from class. 
A boy that sexually abused his sisters and her friends during a playdate.
A nanny that took photos of her sexually abusing a young child in her care and sent the photos to her boyfriend.

In these cases, the offenders did not 'seek out' an opportunity to abuse a child, but rather, found themselves in a situation that enabled them to abuse a child and took it. Sure - some predatory pedophiles may purposely seek such positions, but situational offenders do not. Grooming techniques may be used, but the basic foundation of trust - and most importantly, access, has already been established."

http://themamabeareffect.org/1/post/2015/06/think-all-child-molesters-are-pedophiles-think-again.html