Apparently incriminating gang writings insufficiently testimonial to trigger Confrontation Clause protections when introduced against a nontestifying codefendant.
Expert testimony that gang member was to have access to a weapon at all times and proximity to assault with a puncturing weapon insufficient to establish possession of a weapon.
http://cdn.ca9.uscourts.gov/datastore/opinions/2018/08/31/15-16111.pdf
Since 2011. An occasional commonplacing of the U.S. Circuit Courts of Appeal.
Neither an authoritative statement of the law nor legal advice. Quick work.