Derek Taylor Diego Zanfei, 37, of Dyer, is facing a felony charge after investigators allege he possessed methamphetamine inside the Lake County Jail, where another inmate reportedly suffered an overdose after consuming the drug.
According to court documents, detectives with the Lake County Sheriff’s Department were called to the Lake County Jail on July 30 after jail staff located suspected narcotics inside the facility. A correctional officer requested that the substance be field tested after another inmate suffered an apparent overdose.
Court records state the inmate was stabilized and later told jail staff he had obtained some “ice,” a street name for methamphetamine, from fellow inmate Derek Zanfei. According to investigators, the inmate mixed the substance into his coffee before drinking it, causing the overdose.
After learning Zanfei was allegedly in possession of narcotics, jail staff began monitoring him on surveillance cameras. According to court documents, as officers approached his cell, they observed Zanfei hand an unknown object to his cellmate. Jail staff then searched the cell and recovered a folded piece of yellow paper containing a crystal-like substance.
Investigators used a Thermo Scientific TruNarc Analyzer to test the substance, which allegedly tested positive for methamphetamine. Court documents state the recovered methamphetamine had a field gross weight of 0.4 grams.
Charges filed Aug. 1, 2026:
Possession of Methamphetamine in a Penal or Juvenile Facility — Level 5 Felony
Other pending cases:
Filed July 29, 2026 – Lake County
Possession of Methamphetamine Less Than 5 Grams — Level 6 Felony
Possession of a Narcotic Drug Less Than 5 Grams — Level 6 Felony
Possession of Paraphernalia (Introducing, Prior Conviction of Same) — Class A Misdemeanor
Filed Feb. 19, 2025 – Lake County
Dealing in Methamphetamine (Possession with Intent, 10 Grams or More) — Level 2 Felony
Possession of Methamphetamine More Than 28 Grams — Level 3 Felony
Possession of a Narcotic Drug Less Than 5 Grams — Level 6 Felony
Possession of Cocaine Less Than 5 Grams — Level 6 Felony
Unlawful Possession of a Syringe — Level 6 Felony
Zanfei remains lodged in the Lake County Jail.
