First of all isn't proven that the developer premined before release, seems more a not properly distributed initial supply.
This great piece of inquiry is enough:
https://bitcointalk.org/index.php?topic=740112.0Faking white papers, faking dates 2 years in advance, claiming a launch and dark market usage 2 years ago.
Bytecoin was launched in april 2014, claiming it was around since 2012, to "explain" that 80% was already (pre)mined.
Come on.