From the article:
Two men in their 20s suffered non-life threatening injuries in the blast, including one who had nails in his leg, according to KVUE-TV. South Austin Medical Center officials said the men were in good condition.
The intent, being on the ground, was injury rather than quick death.
Manley originally suggested they could have been hate crimes since all the victims were black or Hispanic, but now says that investigators aren't ruling out any possible motive. The two victims in Sunday's blast were two white males, Manley told ABC News on Monday.
IF these are all from the same bomber, victims are being targeted based on their lifestyles and daily habits. In this last case the bomb seems to have been placed on a route taken by many bicycles (and possibly runners as well).