Investigators admitted to setting up wiretaps to monitor phone conversations during their investigation into the killing of 8-year-old Sandra Cantu of Tracy, according to news reports.

A letter sent to the Stockton Record by the San Joaquin County District Attorney’s Office informed the newspaper that authorities intercepted phone calls to and from suspected killer Melissa Huckaby. The letter listed Huckaby’s cell phone number and the phone number to her grandparents’ home, where she lived with her daughter before her April 10 arrest, the Record reported.

The wiretapped calls were made between April 8 and April 13. Sandra’s body was found stuffed in a suitcase on April 6. Huckaby was arrested on April 10.

The Tracy Press has not received a letter about the reported wiretaps. Neither has the Tri-Valley Herald as of Tuesday evening.

A Tracy Press reporter talked to Huckaby on the landline at her grandparents’ Tracy home on April 10, several hours before the suspect’s arrest.

Huckaby’s grandmother, Connie Lawless, told the Record that she also received a letter informing her that her calls may have been monitored. She told the newspaper that several members of her family’s church got the same letter, which investigators are legally required to send after they secretly listen to a phone conversation.

A gag order prevents anyone officially involved in the case from commenting. The Record reports that on April 8, San Joaquin County Superior Court Judge Richard Vlavianos signed an order to allow investigators to set up wiretaps. The newspaper said it’s unclear whether police monitored phone numbers besides Huckaby’s.

Huckaby has pleaded not guilty to charges of kidnapping, raping and murdering Sandra and “furnishing a harmful substance” to a 36-year-old man and a 7-year-old girl. She remains in solitary confinement in San Joaquin County Jail in French Camp.