Both men are friends in real life and on the server, though I'd say now that they were friends at this point.  The guy who actually created the character was about to finally max out his character after the long three years plus journey, so when he found out all his hard work was deleted, he contacted the local police departments cyber crimes unit.

When the friend was caught, the motive turned out to be simple jealousy than anything else, as he told police he just "Wanted his character." The perp is being charged with unauthorized access, but most likely should've been charged with criminal damage or theft.

The game itself was not mentioned in the article, but a character at said level will probably very expensive to replace, wether it's with money or time.

Credits to Sankaku Complex