The judge found investigators for the Ocean County Prosecutor's Office failed to advise Daniel Bark of his right to remain silent and to have an attorney present during questioning.
Bark denied having anything to do with Alexis Cohen's death during the first 40 minutes of the taped interview. The 25-year-old then said he may have hit Cohen and at one point said he did hit the Allentown, Pa., resident in Seaside Heights in 2009.
The Asbury Park Press reports prosecutors are deciding what to do next because Bark's attorney claims there's no evidence.
Cohen's angry rejection rant became an Internet sensation during "Idol's" seventh season.
Information from: Asbury Park Press, http://www.app.com