• Seven suspects in the attacks on a busy pedestrian thoroughfare in Barcelona and the seaside resort town of Cambrils are dead, four are in custody, and one is unaccounted for.

• Investigators have said the two assaults were not only related but may have been hatched in a house that the plotters had used as a bomb factory. The Islamic State claimed responsibility for the Barcelona attack.

• The dead and wounded in the attacks, which investigators say may have been the product of a far more ambitious plan that had to be abandoned, came from 34 countries.

What We Know

Who is responsible?

The authorities have arrested four people, but it is still unclear who was driving the van that jumped a curb and began speeding down the pedestrian walkway at the center of Barcelona’s most famous street, Las Ramblas.