In a statement, Rob Halpin says the challenges of running for office - starting with the cost - led to his decision.
Halpin didn't mention Emanuel's name, but said he has no plans to endorse or work against any other candidate.
Halpin made headlines a few months ago when he said he wasn't moving out of Emanuel's house, despite being asked to. Emanuel moved back to Chicago, but is living elsewhere.
Halpin is expected to testify at hearings in which several people havein an attempt to .