en_tn/act/16/38.md

when they heard that Paul and Silas were Romans, they were afraid

To be a Roman meant to be a legal citizen of the Empire. Citizenship provided freedom from torture and the right to a fair trial. The city leaders were afraid that more important Roman authorities might learn how the city leaders had mistreated Paul and Silas. (See: rc://en/ta/man/jit/figs-explicit)

they heard ... they were afraid

"the magistrates heard ... the magistrates were afraid"