The Ninth Circuit has determined that the social distinction and particularity requirements imposed by the Board of Immigration Appeals on the definition of a particular social group are reasonable interpretations of the asylum statute. The court further determined that the evidentiary record did not compel the conclusion that former gang members qualify as a particular social group. The court did, however, grant the petition for review with respect to the applicant's request for protection under the Convention Against Torture, noting evidence that former gang members are killed by gang members, and that such acts would constitute torture.
The full text of Reyes v. Lynch can be found here:
http://cdn.ca9.uscourts.gov/datastore/opinions/2016/11/30/14-70686.pdf