Two people were killed and five others wounded in a series of bombings centered on Austin, Tex., this month. The police have said the attacks are linked, and on Wednesday a man suspected of being the bomber, Mark Conditt, 23, blew himself up as officers approached him.

Both people killed by the bombings were black and belonged to prominent African-American families in the city, raising the specter that the violence was racially motivated.

Brian Manley, the Austin police chief, said investigators had not yet determined a motive for the attacks, in which homemade bombs were used to kill and maim people.

Chief Manley said on Wednesday that it was not clear whether more than one bomber may have been responsible for the explosions, which spread fear across the capital of Texas for nearly three weeks.