Mike Verdu, chief creative officer of Zynga Inc. (Nasdaq: ZNGA) quit the San Francisco-based electronic gaming website , becoming the fifth top official to depart in August.

"After a lot of soul-searching, I have decided to go back to my roots and start a new company,"  Verdu wrote on a Zynga Blog.

An alumnus of game giant Electronic Arts (NYSE: EA), Verdu came to Zynga in 2009. Zynga plans to invest in his new venture, which will develop new mobile games, a company representative said.

Zynga shares fell 4 cents to $3.04 in early trading. They're down nearly 70 percent from the initial public offering last December.