Ya salió el peine

Ya salió el peine literally means "the comb already came out". It is used to convey that finally some crucial information about a matter has been revealed. A mystery has been solved or the culprit's identity has been disclosed. 

Example:

Enrique: ¡Chale! ¿No te parece difícil de entender que el achichincle del gobernador lo haya balconeado de que tenía una amante?
Marcelo: Nel, pus si ya salió el peine. El achichincle estaba bien clavado con la amante.

Enrique: Geeez! Don't you find hard to understand that the governor's aide made public the relationship of the governor and his lover?

Marcelo: Nope, it's all clear now. The aide was head-over-heels in love with the guv's lover.