Police link two more bombings in Texas capital to earlier attack

All the victims, including a 39-year-old man who died in the March 2 blast, were either African-American or Hispanic, Manley said.

“We cannot rule out that hate crime is at the core of this but we are not saying that that is the cause,” Manley told a news conference.

He warned residents to watch out for unexpected boxes left outside their homes, without picking them up, and to report anything suspicious to police.

The attacks took place as Austin hosted thousands of out of town visitors for its annual South by Southwest festival.

In Monday’s suspected attacks, a package bomb killed a 17-year-old youth and injured a woman at their Austin home. Later, an explosion put a 75-year-old Hispanic woman in critical condition with “life threatening injuries,” Manley said.

“This is the third in what we believe to be related incidents that have happened over the past 10 days,” he said.

Monday’s blasts were in homes about four miles (6 km) apart in east Austin, while the March 2 incident occurred at a house in the city’s northeast Harris Ridge neighborhood, about 12 miles from downtown.

The March 2 blast was initially investigated as a suspicious death but is now being treated as a homicide, Manley said.

On Monday, the 17-year-old found a package outside his house and brought it into the kitchen, where it exploded, Manley said. The woman, in her 40s, was taken to an area hospital with injuries that were not thought to be life-threatening.

After the March 2 explosion, Austin police said they had no indication the blast was related to terrorism.