Erik Nisbet and colleagues had a survey in the field when bin Laden was killed. Comparing those interviewed before and after his death — and controlling for any differences between these two groupsin terms of demographics and other factors — they find:
Americans found Muslims living in the United States more threatening after bin Laden’s death, positive perceptions of Muslims plummeted, and those surveyed were less likely to oppose restrictions on Muslim Americans’ civil liberties.
For example, in the weeks before bin Laden’s death, nearly half of respondents described Muslim Americans as “trustworthy” and “peaceful.” But only one-third of Americans agreed with these positive terms after the killing.
Most of the changes in attitude happened among political liberals and moderates, whose views shifted to become more like those of conservatives, the survey found.
Nisbet offers this explanation:
bq. The death of bin Laden was a focusing event. There was a lot of news coverage and a lot of discussion about Islam and Muslims and Muslim Americans. The frenzy of media coverage reminded people of terrorism and the Sept. 11 attacks and it primed them to think about Islam in terms of terrorism.
More is here. I would not have anticipated this shift, but if media coverage and priming is the likely culprit, then I suspect that the shift was likely short-lived.