A Boeing 737 airliner crashed in the Russian city of Kazan yesterday, killing all 50 people on board and spotlighting the poor safety record of regional airlines that ply internal routes across the world’s largest nation.

As the lone surviving suspect in the Boston Marathon bombing lay in hospital under heavy guard, the American Civil Liberties Union and a federal public defender raised concerns about investigators’ plan to question Dzhokhar Tsarnaev without reading him his rights.