Hate crimes surged at several points during and after the 2016 U.S. presidential election. Observers argued that hate crimes, especially against Muslims, increased due to inflammatory rhetoric. Did anti-Muslim hate crimes decline after the salience of Muslims receded? Or did emboldening and organizational effects on hate crimes endure? Here, we show that a sudden mid-2017 decline in media discussion of Muslims and in online communities was associated with a large and sustained drop in anti-Muslim hate. At nearly the same time as these shifts, however, we observe an increase in violent hate crimes committed against Jews, and Granger causality tests demonstrate that week-to-week changes in online extremist speech targeting one group versus another also predicted subsequent shifts in hate crimes and bias incidents. Platform-level and within-individual analyses of online social media users suggest that increased anti-Jewish speech was partly driven by far-right communities and extremists who previously promoted anti-Muslim speech.