Matter of Valenzuela Gallardo, 25 I&N Dec. 838 (BIA 2012) (California conviction of accessory after the fact, in violation of Penal Code 32, is an aggravated felony "obstruction of justice" offense if a sentence of one year or more is imposed on any single count).
http://www.justice.gov/eoir/vll/intdec/vol25/3758.pdf.