Mehmet nereye kayboldu ! Where did Mehmet! Thank you

İt means:

Where did Mehmet disappear?

or maybe it means:

Where did Mehmet take his road/way.

(Where did he go?)

You can say:

*Mehmet nereye gitti? (Where did Mehmet go?)

 It means something like that "Where the hell did Mehmet go?"

Aha, New thing to learn =)

 Where did Mehmet disappear?  Yours is better.