No, I don't think the national press will pick this up. They haven't covered it yet, so why start now? I wouldn't call that mysterious, though. The mainstream US press are mostly in the thrall of sex denial.
re: 'biker gang,' the prosecution took what seemed to be an odd angle in their pursuit of this case.
According to Kara Dansky (herself an accomplished attorney) they didn't need to establish a motive for the crime. The physical evidence and witness testimony was overwhelming.
But for reasons of their own, the prosecutors developed a narrative of motivation for the crimes that had to do with Rivers' and Reed's involvement in the "Deviants" "all-female" biker group.
From a news story last fall:
"Still, the prosecution memo says that when police asked Rivers in the immediate aftermath of the killings if they were in any way related to the Deviants, she [sic] denied it."
"This has nothing to do with that," Rivers said, according to court records. "This was personal."