Well it's possible they could have installed a keylogger or something to track your keystrokes. Not sure if there are programs that can record your screen or something though.
Some Keyloggers do record Screenshots as well. And also track what websites you go to.
Did the guy do it? Dunno.
Is It possible? Yes.
Though do keep in mind most keyloggers i know of you need to have access to teh computer to get the info off it. Though i can see someone easily writing a program to access it remotely.
I wrote a keylogger that sends all keystrokes to e-mail so yes a keylogger can be use remotely don't search for keyloggers format your pc the keylogger could be hidden and merged with a .exe file --- playing re6 with 8x sparse grid ss with 32xs(2x2 ss + 8 ms)+ mixed sample x128 + 32 forced anisotropic then I hear ps4 is powerful than my pc