ABC News(AUSTIN, Texas) — A second explosion rocked Austin, Texas, hours after an earlier blast, which was apparently caused by a package left on a porch, killed a teen and injured a woman.

The first blast, reported about 6:44 a.m., killed a male teenager and injured a woman in her 40s. The second explosion today injured another woman, with authorities evaluating whether a second person was also hurt, according to the Austin Police Department.

Investigators said earlier that first blast today may be connected to a March 2 blast in Austin because of the composition of the explosive device used. The police chief declined to discuss the construction of the explosive device or what specific elements make it look similar to the earlier one.

The explosion “is very similar to the incident that occurred in Austin back on March 2, and if you’ll remember, that incident also occurred in the morning hours when the victim, in that case, went out front and found a package on their front steps that exploded causing that individual’s death,” police chief Brian Manley said at a news conference Monday.

What is known about today’s blasts

The first explosion today occurred at a single-family house in the northeast section of the city and appears to have been caused by a package that had been placed on the porch of a home rather than delivered by a mail service, police said. Police believe the explosion happened after residents took the package inside to open it.

“What we understand at this point is that earlier this morning, residents went out front, and there was a package on the front doorstep. They brought that package inside the residence and as they opened that package, both victims were in the kitchen and the package exploded causing the injuries that resulted in the young man’s death and the injuries to the adult female,” Manley said today.

Authorities have warned residents that if they receive a package they are not expecting, they should contact the Austin Police Department.

The FBI told ABC News that it was responding to the first reported explosion and assisting Austin police, who are the lead agency handling the situation.

The Bureau of Alcohol, Tobacco, Firearms and Explosives has sent staff from both its national response team and reinforcements to bolster local field resources. The national response team is the entity that goes in to major incidents to investigate complex fires and explosions – most recently the church fires in the south and the Oakland warehouse catastrophe.

An explosion earlier this month

Today’s blasts follow the explosion on March 2, which police received a call about at 6:55 a.m. that day.

The victim in that explosion, Anthony Stephan House, died from his injuries after being transported to a local hospital.

“That case was being investigated as a suspicious death,” Manley said today. “It is now being reclassified and is now a homicide investigation as well. We are looking at these incidents as being related based on similarities that we have seen and the initial evidence that we have on hand here today compared to what we found on the scene of that explosion that took place a week back.”

Manley noted that “we don’t know the motive behind these” events though he said that all three of the homes involved in blasts today and on March 2 blast had African-American residents.

“We can not rule [out] that hate crime is at the core of this, but we’re not saying that’s the cause as well,” he said.

Today’s blasts come at a particularly busy time for Austin, as the city hosts the annual SXSW music, film and technology conference from March 13 until March 18.

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