A number of things point to this...
*He was initially IDd by Oates as Iranian Muhammed Alam
http://www.freerepublic.com/focus/news/2908624/posts?page=129
*He did this as the calendar flipped to Ramadan
*He noted his new interest in illicit sex as 'shenanigans'
*New York and Paris went into immediate panic mode.
None of this compelling, just odd for a 'lone gunman'.
Umm...what does “Shenanigans” have to do with Islam?