AUSTIN, Texas (AP) — Families of two people killed by package bombs left on their doorsteps in Austin knew each other and were connected through local activism in the black community, a civic leader said Tuesday. But it was not clear how they might be tied to a third household where a package bomb also exploded.

Investigators have said the three blasts that killed two people and wounded two others could have been hate crimes since all the victims were black or Hispanic. But they also said they have not ruled out any possible motive.

Draylen Mason, 17, was killed and his mother wounded when a p...