Leonardo DiCaprio’s stepbrother, budding actor Adam Farrar, 28, was arrested in the Los Angeles beach town of Marina del Rey on Wednesday on suspicion of attempting to murder his girlfriend, whose identity was withheld. Police say Farrar, who was charged with one count of attempted murder and one count of making terrorist threats, mentioned his relationship to the “Titanic” star to authorities at the time of his apprehension. Police would not say whether this was an attempt to avoid arrest. They also would not reveal whether or not a weapon was involved. DiCaprio, 25, had no comment about the incident, his spokesman said. Farrar is being held on a million dollars bail at the Twin Towers Correctional Facility in L.A. and is expected to be arraigned on Friday.