Inflammatory, race-based comments on Twitter by the youngest accused, 15-year-old James "Bug" Edwards, before last week's drive-by murder in the city of Duncan led to speculation Mr Lane, 22 from Melbourne, was targeted because of his race.
In one Twitter post Edwards wrote: "90% of white ppl are nasty. #HATE THEM".
In another post Edwards, a champion junior wrestler who hoped to represent the US at the Olympics, claimed to have knocked five white people out after July's controversial acquittal in Florida of neighbourhood watch co-ordinator George Zimmerman for the second-degree murder of 17-year-old Trayvon Martin.
"Ayeee I knocced out 5 woods since Zimmerman court!:)," Edwards, using the derogatory word "woods" to describe whites, posted.
Stephens County District Attorney Jason Hicks said there was not enough evidence collected so far in the investigation to indicate Mr Lane's killing was motivated by race.
"At this point, the evidence does not support the theory that Christopher Lane was targeted based upon his race or nationality," Mr Hicks said in a statement.
"The evidence is insufficient to establish that race was the primary motive in the murder of Christopher Lane."