This story was updated with information from a news briefing at 3:46 p.m. CT March 12, 2018.

Explosive packages left on the doorsteps of three Austin residences have killed two and injured at least two more in the span of ten days. The first explosion occurred on March 2 and the second happened March 12, and Austin police are not ruling out the possibility of hate crimes, saying they believe all explosions are related and are warning residents to be cautious of any suspicious packages left on their property.

“We have two cases that are very similar that have both resulted in a loss of life,” Austin police chief Brian Manley said Monday morning. “Until we find who committed this act and take them into custody, it is appropriate for residents to be concerned if you receive a package that you were not expecting, a package that is not marked properly, or is not from someone that you know. It’s better to be safe and give us a call.” By Monday afternoon, Manley had said that police believe all three incidents are related.

On Monday afternoon, Governor Greg Abbott weighed in on the bombings, offering the support of state law enforcement and a $15,000 reward for information leading to the arrest of the bomber.

“I want to assure all Texans, and especially those in Austin, that local, state and federal law enforcement officials are working diligently to find those responsible for these heinous crimes,” Abbott said in a written statement. “As the investigation continues, the State of Texas will provide any resources necessary to ensure the safety of our citizens, and quickly bring those guilty to justice.”

A seventeen-year-old boy died and an adult woman was hospitalized with non-life-threatening injuries after a package they received at their East MLK neighborhood home exploded at 6:44 a.m. Monday. According to police, one of the residents went outside and found a package on the front doorstep. When they brought it inside and opened it in the kitchen, the package exploded. Police have not yet released the victims’ names.

Later Monday a second explosion was reported in the 6700 block of Galindo Street in East Austin. A woman in her seventies was taken to Dell Medical Center with potentially life-threatening injuries, the Austin–Travis County EMS reported. The Austin Fire Department said this incident also resulted from a package explosion, but police have not said whether it is connected to the other two explosions.

Manley said the woman found the package by her front door and it detonated when she picked it up. He warned Austin residents against handling suspicious packages and, instead, call police if they see anything unusual.

The fatal incident mirrored another explosive-package death in Austin less than two weeks earlier: 39-year-old Anthony Stephan House was killed after he received a package at his Harris Ridge neighborhood home on March 2. The package exploded after House opened it. He died from his injuries shortly after being transported to the hospital, according to KEYE. “It’s so tragic,” Daniel Sledge, one of House’s neighbors, recently told KEYE. “Everybody in the neighborhood is on pins and needles. Even seeing delivery drivers and Amazon boxes on the porch right now. Especially while we don’t know very much.”

After Monday’s explosion, investigators have reclassified House’s death from a suspicious death to a homicide. “We are looking at these incidents as being related based on similarities that we have seen in the initial evidence we have on scene here, compared to what we found at the explosion that happened a week back,” Manley said at the scene of Monday’s explosion. “We are looking at anything that might tie these two together, but again, there are similarities that we cannot rule out that these two incidents are in fact related.” Manley declined to discuss in detail what those similarities were.

Manley said that while investigators are still searching for a motive, the incidents are under investigation as possible hate crimes because the victims in both cases are African-American. The third bombing involved an Hispanic woman.

“We cannot rule out that hate crime is at the core of this,” Manley said. “We’re not saying that’s the cause, we’re just looking at any possible motivations that would link these two cases together.”

Austin package explosion
Police investigate at the 4800 block of Old Fort Hill road in East Austin, where a package exploded and killed a 17-year-old boy and injured an adult woman.Photograph by Leif Reigstad

There’s no reason to believe so far that the packages came through the U.S. Postal Service, which reviewed its records and didn’t find a package in its system that would match the one that exploded on Monday, according to Manley, who also said that so far it appears that the packages were not delivered through any mail service. The FBI and the federal Bureau of Alcohol, Tobacco, Firearms and Explosives are jointly investigating the incidents with APD.

Both packages were believed to have been delivered overnight, with the victims finding and opening them in the early morning hours, Manley said, adding that there is no indication that the packages are marked as though they are from any specific vendor, such as Amazon.

“If you’ve received a package that you are not expecting, that is from someone you did not expect to receive a package from, or that gives you any cause for concern, call 911,” Manley said. “We believe the possibility that [these incidents] are related exists. We are not going to tolerate this in Austin. Every stop will be pulled out.”