Court filings show the FBI relied heavily on a long‑time paid informant and at least one undercover agent in a Southern California counterterrorism probe that led to arrests, after prosecutors said they disrupted a plot to detonate backpack bombs on New Year’s Eve.The arrested suspects include Audrey Illeene Carroll, Zachary Aaron Page, Dante Gaffield and Tina Lai, and filings say agents recovered PVC pipe, suspected potassium nitrate, charcoal and pistol primers and seized an eight‑page plan labeled Operation Midnight Sun that named multiple “Amazon‑type” logistics sites as targets.The case has prompted questions about entrapment and FBI tactics from defense attorneys and civil‑liberties advocates amid official statements calling the cell violent and describing the intervention as preventing a credible, imminent terrorist threat.