Police detained Farrar, 42, in Collin County on Jan. 24. The charges include misdemeanor counts of possession of a dangerous drug, theft and harassment by phone. Jail records show all of the charges were outstanding warrants issued by Los Angeles authorities.
The arrest reportedly occurred when Farrar attempted to visit his 38-year-old girlfriend Charity Moore at the Collin County Sheriff's Office.
"Adam Farrar came in to visit an inmate, and we arrested him at that time," Lt. John Norton of the Collin County Sheriff's Office tells PEOPLE. "We were aware of the warrants out for him in Los Angeles."
"He is still in custody at this time," Norton adds. "Our district attorney's office will work with the state of California and coordinate what happens next."
Los Angeles County District Attorney spokeswoman Jane Robison tells PEOPLE: "A bench warrant was issued last December for Farrar's drug case – he had pleaded guilty to possession of heroin and is supposed to be in a drug diversion program. He was charged in July 2013, he pleaded guilty in Sept. 2013, and he was due in court on Dec. 6, 2013, for a progress report, which resulted in a bench warrant."
On Jan. 20, Farrar's girlfriend, Moore, was arrested on misdemeanor charges including three counts of possession of a controlled substance, two counts of possession of a dangerous drug, theft of property under $500, and contributing to her child's non-attendance at school.
The couple's 6-year-old daughter, Normandie, has been reported as a Los Angeles County missing child since July 31, 2013, and she is listed as "abducted" on the country's missing-children site.
Lt. Norton, of the Collin County Sheriff's Office, said he was "not aware of a missing child. There was no child with [Farrar'] when he came in."
Moore's father, Don, insisted to Radar Online that "Normandie's safe … She's a beautiful child and she's not 'missing.' She was with her mother, and where she is now is nobody's business."
A Start in Show BusinessThe stepbrothers became family after George DiCaprio, Leonardo's father, married Farrar's mother, Peggy, when their sons were in preschool.
Growing up in Los Angeles, DiCaprio, 39, had a close relationship with Farrar while both navigated show business as kids. Farrar starred in TV commercials and landed parts in series such as Eight Is Enough and Battlestar Galactica. Their paths diverged when Farrar outgrew acting during his high school years and had run-ins with the police in his 20s.
In 2000, Farrar was arrested in L.A. on suspicion of attempted murder of his then-girlfriend and making terroristic threats. He was held on $1 million bail after bragging about his DiCaprio connection, but police declined to charge him within the required 48 hours after his arrest.
With reporting by ALICIA DENNIS and KEN LEE