Authorities are operating under the assumption that the bombs were made by the same person.
Here is what we know about the Austin bomber’s habits:
- Prior to the explosion Sunday, the three bombs were left in packages at homes.
- Sunday's bomb was tripwire-activated.
- Sunday's bomb was in a different geographical area than the other three bombs.
- The victims of the first three bombings were African-American and Hispanic. Sunday night's victims were white.
- Fred Burton, a security and terrorism analyst at Austin-based Stratfor, told the Austin American-Statesman that he believes it is the same person doing the bombing. He may have changed bombing locations and methods to throw investigators off, Burton said.
- Common household items were used to construct the first three bombs, the American-Statesman reported.