No. And pretty obviously not, look at the response. For people to hear about political assassinations it has to make the news and be widely discussed. There isn't any point murdering artists to "keep fear high", that just gives them something to create art about.

The usual tactic is to brand people as troublemakers then try and limit the news coverage they get. Or hit them with a smear campaign which is cheaper, easier and less likely to attract negative publicity like an assassination would. As a bonus the smear approach also directly discredits the message they were spreading.