The main suspect in the Texas serial bombings case is dead, having "detonated a device" with shots fired when officers approached his car, police say.
The man, who is believed to be responsible for a series of parcel bombs in the city of Austin, Texas, has not been formally identified but was named as 23-year-old Mark Anthony Conditt.
The man died after he detonated an explosive as officers approached his car following a chase in Round Rock, about 32km north of Austin.
The incident follows bomb attacks in the Austin area that began in Austin in early March - involving package bombs and a tripwire - which police said were all related.
Two people have been killed and six injured in the bombings.
- 2 March: A device explodes at Anthony Stephan House's home in Austin, killing the 29-year-old man
- 13 March: Draylen William Mason, 17, is killed and his mother is critically injured after he brings a package inside his home from the doorstep in Austin
- Hours later, a 75-year-old Hispanic woman, who has not been named, is injured by another package in the state capital
- 18 March: A device injures two men who may have set off a tripwire while walking along a street in Austin
- 20 March: A parcel bomb explodes at a FedEx depot in Schertz, slightly injuring one person. Police said the parcel had been due to be shipped to Austin
Officials warned more bombs may still be in the area
Austin police used footage from the scene of the latest parcel bomb explosion to identify the man, then used a search engine to gather information on his online browsing history which showed searches on facilities used to ship packages.
Authorities later managed to locate his vehicle. In the early hours of Wednesday, local and federal officers took up positions around a parking area near a hotel in Round Rock.
As they waited for tactical teams to arrive, the vehicle started to drive away and officers pursued it. When the vehicle eventually pulled over, armed officers approached but the suspect then detonated a bomb, injuring one officer. Another officer opened fire.
Police later confirmed that the blast had killed the suspect.
Austin police chief Brian Manley said that local residents should "remain vigilant", and urged anyone who noticed a suspicious package to contact the authorities.
"We don't know where the suspect has been over this past 24 hours," he said, adding that it was possible that additional devices may have been distributed.
Officials said the man lived about 30km from Austin in a home with two flatmates in Flugerville, about 32km south of the city. Texas Governor Greg Abbot said the two flatmates had been talking to authorities, and were not suspected of any crimes.
Mr Abbot said the suspect did not destroy his online footprint, which may provide investigators with a "treasure trove of information that should shed light on who he is, what he did, and why he was doing it".
According to USA Today, Conditt attended the Austin Community College from 2010-2012 but did not graduate.
The Austin American-Statesman newspaper reported that he was homeschooled by his mother during his high school years. His parent's home was being searched by authorities, it said.
"I officially graduated Mark from High School," his mother wrote on Facebook in a 2013 post showing her son.
"He's thinking of taking some time to figure out what he wants to do ... maybe a [religious] mission trip," his mother wrote.
The newspaper reported Conditt had recently worked for Crux Semiconductor in Austin as a "purchasing Agent/buyer/shipping and receiving", citing a profile on a job recruiting website.
US media have uncovered a 2012 blog which was written under the suspect's name and appeared to be for a university course that he attended.
In the blog called "Defining my Stance", he purportedly describes beliefs that "gay marriage should be illegal", opposition to abortion and why the sex offender registry should be eliminated.
In the blog, he defines himself as "a conservative".
"But I don't think I have enough information to defend my stance as well as it should be defended," he says, adding that he is taking the course "because I want to understand the US government, and I hope that it will help me clarify my stance".