IIRC there was some type of connection between the first three bombings. Have you seen that?
Here is what I meant by a connection between the victims.
“House, remembered by friends as a quiet and motivated man, left behind an 8-year-old daughter. He went to high school in Pflugerville, an Austin suburb, where he ran track and played basketball.”
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“There was also speculation that the victims were targeted because of close connections. Dixon, stepfather to House [first victim], is friends with Mason’s[second victim] grandfather Norman, both prominent fixtures at a local black church.”
http://www.chicagotribune.com/news/nationworld/ct-austin-bombing-victims-20180321-story.html
“The first three explosions in Austin involved cardboard packages left in front yards or on porches. The parcels weren’t delivered by the US Postal Service or services such as UPS or FedEx, police have said.”
https://www.cnn.com/2018/03/21/us/austin-explosions/index.html
So Conditt randomly placed package bombs at two different addresses and happened to kill two guys who had a connection. One of whom went to Pflugerville High School.