The brains behind the Machine, Mr. Finch is a skilled programmer who created the device to detect violent acts before they happen by analyzing data from surveillance cameras, electronic communications, etc. Along with his team, he uses his backdoor access into the government controlled Machine to save lives.
Regardless of whether you are the victim or the perpetrator, Mr. Reese and Mr. Finch will find you. After all, you are being watched and the Machine never lies. This Person of Interest shirt is for those who enjoy the TV show or who live in fear that they are being watched.