The most colorful candidate in this year's race for mayor has run into a major stumbling block.

Former police detective and Fox News commentator Bo Dietl has been denied in his bid to run on the Republican party line. 

Because he is not registered in the party, the move would have required three of its five county chairs to grant a waiver known as a Wilson Pakula. But it became clear during a conference call last weekend that Dietl had little GOP support.

Dietl told NY1 he may still seek other party lines and, if necessary, will run on his own line in the general election.