LIVERMORE -- A registered sex offender employed by the state as a tax auditor was charged Monday with sexually abusing a 9-year-old boy he knew through a friendship with the child's mother, authorities said.

Timothy Rodriguez, 48, was taken into custody at his home in the 1200 block of Higuera Court at 1:55 a.m. Monday after allegations surfaced that the man had repeatedly molested the boy from 2010 to 2013 -- and as recently as July 28, court documents show. The boy first told his mother about the alleged abuse on Sunday evening, Livermore police Sgt. John Hurd said.

Timothy Rodriguez, 48, of Livermore
Timothy Rodriguez, 48, of Livermore (Photo made public by Megan's Law)

The young boy described five incidents of sexual abuse beginning when he was six years old in 2010, three of which occurred in Livermore and two of which occurred in the boy's home out of state, court documents show. The boy said that in all five instances Rodriguez grabbed his hands and/or feet and rubbed them against his genitals.

Rodriguez, a registered sex offender convicted in a 1989 Fremont child molestation case, was taken into custody after officers arrived at his house and spotted a .22-caliber rifle laying in plain view in his master bedroom, according to court documents. While the firearm was discovered during the protective sweep, the weapon was not related to the current sexual abuse in question, Hurd said.

Rodriguez was interviewed and booked into Santa Rita Jail on charges of continuous sexual abuse on a child under 14, as well as being a felon in possession of a firearm, Hurd said. On Tuesday, the Alameda County District Attorney's office charged him with one count each of the same allegations, along with special "second strike" enhancements because of his previous child molestation conviction.

Rodriguez remains in jail without bail, facing a minimum 25-year sentence and maximum life sentence if convicted, Hurd said. Livermore police detectives are finalizing their investigation into the allegations of sexual abuse, which includes determining whether any other children were in contact with the man.

Court records reveal that Rodriguez committed the 1989 crime while volunteering as a youth leader in a local church group, but police have been unable to determine whether he was involved in any religious organizations in the city of Livermore, Hurd said.

Anyone with information about Rodriguez is asked contact Sgt. John Hurd at 925-371-4857.

Contact Erin Ivie at eivie@bayareanewsgroup.com. Follow her at Twitter.com/erin_ivie.