In 'Found Photos' style, a pair of Google Street View car drivers unknowingly take a photo of a dangerous cult performing a ritualistic killing in a remote field and are pursued by them. Detectives are left with an abandoned car and a series of mysterious photos in order to find the pair before it's too late. (Inspired by these types of lists – http://www.viralnova.com/creepiest-things-on-google-maps/

"When two homies from the Bronx are abducted by the Plattsburg Ku Klux Klan, the only thing that can save their lives is a pair of vague Google Street View photos left in their abandoned car."

I guess that a detective/FBI agent will try to find them is clear.

You have a very original idea but not a logline.

Something like:

"When a pair of Google Street View car drivers disappears, a tenacious detective must analyze the mysterious photos they took in order to find them before it's too late."

Or

"When a pair of Google Street View car drivers accidentally takes pictures of a strange cult performance and suddenly disappear, a tenacious detective must analyze the mysterious photos they took in order to find them before it's too late."

The theme is great in my opinion, the logline needs to be elaborated as the other commenters also mentioned.