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AUSTIN, TX (CNN) — A suspect in a wave of bombing attacks in Austin killed himself inside his car with an explosive device early Wednesday as authorities closed in, police said.

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Police have identified the Austin serial bombing suspect as 23-year-old Mark Anthony Conditt, according to a source with direct involvement in the investigation.

Since the bombings started on March 2, investigators frantically searched for clues, calling the attacks the work of a “serial bomber” who increasingly changed tactics. The bombings killed two people and left the Texas capital terrorized with fear for 19 days.

In the past 36 hours, law enforcement received information directing them to a person of interest, Conditt, who ultimately became a suspect. Surveillance teams tracked his vehicle to a hotel in Round Rock, north of Austin.

As officers waited for tactical units to arrive on the scene, the man began to drive away and later stopped on the side of the road.

“As members of the Austin swat team approached the vehicle the suspect detonated a bomb inside the vehicle,” Austin Police Chief Brian Manley said.

Conditt died inside the vehicle.

Authorities don’t know whether he acted alone or what his motive was.

“He is responsible for all the incidents in Austin,” Brian Manley said. “This is the culmination of three very long weeks in our community.”

Investigators are questioning Conditt’s roommates. He was home-schooled then dropped out of community college.

“Austin bombing suspect is dead. Great job by law enforcement and all concerned!,” President Donald Trump tweeted.

Even though Conditt is dead, he may have already planned other attacks, so the threat may not be over.

“Continue to be vigilant, we are concerned there are still other devices out there,” said ATF Agent Fred Milanowski.

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On Tuesday a package exploded at a FedEx sorting center near San Antonio and a second unexploded bomb was discovered on the same day at another FedEx facility near Austin.

Those two packages are connected to four previous bombings in Austin that left two people dead. FedEx said the person who sent the package that exploded Tuesday also shipped a second one that was turned over to law enforcement officials.

FedEx said it provided authorities with “extensive evidence” from its security system on the packages and the person who shipped them.

In the incident near San Antonio, the device detonated on an automatic conveyor. A female employee was treated on site and released. The FedEx facility was not the intended target.

A possible explosion reported Tuesday night at a Goodwill store in Austin turned out to be unrelated. In that incident, an employee was injured by two “artillery simulators” in a donation box, said Ely Reyes, Austin’s assistant police chief. The employee was treated and released from a hospital, Reyes said.

Investigators believe Conditt was behind all the devices because they had a lot of consistencies.

The Explosions
Of the four previous explosions in Austin, the first three involved cardboard packages left in front yards or on porches. They weren’t delivered by the US Postal Service or services such as UPS or FedEx, police say.

Those three explosions — one on March 2 and two more on March 12 — killed or wounded three African-Americans and one Hispanic person. They happened in east Austin areas with predominantly minority residents. Some residents expressed concern the attacks might have been racially-motivated.

The Victims
The first explosion killed 39-year-old Anthony Stephan House on March 2. The second blast on March 12 killed 17-year-old Draylen Mason. The third blast happened several hours later and critically injured a 75-year-old woman.

Those three blasts all happened after someone left explosives-laden packages on the victims’ doorsteps.

In the fourth blast, a device was triggered by a tripwire, injuring two white men in a predominantly white area.

Police have not ruled out the possibility that those bombings could be hate crimes. They urged residents to pay attention to their surroundings, and not approach or touch anything that looks suspicious.

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