I got all of the questions 'Correct' and Tiernan tried selling out McCaffrey by claiming he gave the girl a death threat, or at least vocally expressed doing her harm. I went back to McCaffrey and said that, and then he accused Tiernan saying he ended up at his place drunk with the murder weapon and the clothes and he was going to help him out.
Back again, Tiernan broke down and pretty much gave a half confession. I walked away from that having a bad feeling and noticed I could use the phone, at which point Phelps asked about the background info/criminal record on McCaffrey, which then revealed he was abusive to women before because that woman took/stole something from him, and when he was confronted with that information he pretty much snapped shouting something along the lines of "She got what she was coming to her!". Profanity excluded.
So yeah, after that it was easy to pick. xD
XBL | NemesisTheory. Deadly Premonition: Game of the Year, every year.