In Alex's images, the people are unaware of having had their picture taken because she´s doing something called stalker photography. Filmmaker MP Cunningham captures her rare form of photography in the film The Observer:

I was introduced to Alex about a year ago through a mutual friend. I had heard about a "stalker photographer" from a couple people and was pretty intrigued. After about a two month process of trying to get her to sit down with me she finally agreed to tell her story. I was pretty blown away. Seeing the world through her eyes has been a unique experience to say the least. Her photos are unreal. Can't say I completely agree with her craft but its very beautiful in its own way. [...]

I'm not entirely convinced that this is a true story and that the girl in the film is the real Alex, but nevertheless I find the film and story intriguing:

Here is an interview with MP Cunningham made by Directors Notes.

You find more of Alex's photography here.