Two Kinds of Stranger by Steve Cavanagh

Ellie Parker had everything.
Perfect husband. Perfect apartment. Perfect friends and the perfect job.
As an internet celebrity – famed for her random acts of kindness – everyone knew it.
So when a betrayal causes her to lose it all, millions of people are watching.

But even at her lowest, Ellie will always help someone in need.
Which makes her the perfect target for a sadistic game.
Because as she soon learns, you can never trust a stranger – and a seemingly random encounter plunges her into a nightmare worse than she ever imagined.

The only person she can turn to is conman turned trial lawyer Eddie Flynn, who must take on a case where nothing is what it seems. With the most cruelly ingenious mind manipulating events from the shadows, everyone is in danger – including Eddie and his family.