Sylar killed Elle with little apparent regret. He couldn't forgive her for her part in making a murderer out of him. That's why he said that they were both "damaged goods". They did seem to share love, but Sylar is too damaged to accept that love is possible even in damaged goods. And he's manipulated so many women he may not be able to recognize sincerity. Look at how he pushed away Luke and Micah.
thats not true he DID mention her like once. when he had like trapped meredith, claire, noah & angela in primatech or wtv he was like "....and now elle's dead...." but still he needs to mention her more!!! :(
HE PROBABLY THOUGHT SHE DIDNT LOVE HIM! I was sooooo effin pissed off at him! How could he forget elle?!?!?!?!?!?!?!*yells at sylar* HEY HELLO I THINK UR FORGETING A CERTAIN CUTE BLONDE!!!!!