Iphone/android spy application/software

Hello, I would like to spy a given contact Whatsapp so i can monitor the conversation that contact is making with others. There are 2 spy applications already on sale on the market but the problem is that those applications need to be installed directly from the target device (something almost impossible to make, unless you are genius enough to let your friend/wife/husband give you their iphone/android for 5 minutes so you can quickly install the spy application.) What I want is something similar but with the ability to install it remotely, maybe by sending her/him an image so he/she download it to see it, but it also trigger the install of the spy application. Other option is that Whatsapp stores the messages of people on their servers, so the thing would be to build an app. that is able to hack/enter and pull out the given number messages. look this video: [login to view URL] but this guy seams to be a scammer! Please tell me your comments questions. thanks