SANTA ANA, Calif.—A former addiction care center employee who was driving under the influence of various drugs when he struck a Costa Mesa firefighter bicycling on a Mission Viejo sidewalk was convicted today of second-degree murder. Stephen Taylor Scarpa, 28, is facing 15 years to life in prison at his sentencing, which is scheduled for Dec. 10. Jurors deliberated for about an hour Tuesday and another three hours Wednesday before reaching a verdict. During his trial, Senior Deputy District Attorney Dan Feldman told jurors that Scarpa was “loaded” on various drugs when he left a party in Westminster on Nov. 3, 2018, to drive home. Scarpa wound up striking Costa Mesa Fire Department Captain Mike Kreza, 44, who was bicycling on Alicia Parkway near Via Burgos around 8 a.m. that day. Feldman said the defendant had ingested methamphetamine, fentanyl, and “undefined downers” before the deadly collision. “He’d been up for …