A 16-year-old suspected of putting a swastika on a vehicle belonging to an interracial family in unincorporated La Mesa could be charged with a hate crime, a sheriff's detective said today. The youth was arrested Friday and taken to Juvenile Hall, where he was booked on suspicion of criminal threats and putting marks on private property to terrorize for the alleged crime reported on June 30, San Diego sheriff's Detective Ed Southcott said. The address where the alleged crime occurred was not made public. The youth's name was withheld, because he is a juvenile. The suspect appeared to have acted alone, according to the detective, who said the case was considered a hate crime.