Yeah, they knew each other, it's canon.
In the episode 11, there is a discussion like
Sylar : I know you...
Eden : I lived next door to Chandra Suresh.
Sylar : That wonderful ability... and all this time, you were the girl's next door !
And then he points that she knew and she could have killed him, and she did not.
I have written about them in these time... would you be interested in reading it ? It's in French, but I think it would not be a problem...