AUSTIN, Texas — Before the intense, three-week manhunt in a series of bombings came to a sudden, explosive end in a roadside ditch in the early hours of Wednesday, the FBI agents and police investigators tasked with identifying the bomber seemed at times to be chasing ghosts.
They ran down theories of drug dealer retaliation gone awry and struggled to understand the significance of family connections between the victims. All the while, the bomber escalated his attacks — first using a trip wire, then by sending explosives through FedEx.
But behind the scenes, investigators had used cell tower data to tie Mark Anthony Conditt, a 23-year-old from the Austin suburbs, to the bombing sites and other important locations, Texas’s governor said Wednesday. And when the suspected bomber used FedEx, law enforcement caught an even bigger break: He had been captured on a store’s video surveillance system.
The furious manhunt for Conditt culminated after one of the surveillance teams scouring the area spotted his red SUV in a hotel parking lot in Round Rock, about 18 miles north of Austin, the Texas capital.
Officers closed in, and Conditt ultimately detonated a bomb and was killed. The bloody confrontation brought an end to three weeks of terror in which investigators believe Conditt planted at least six bombs, either at homes or in the FedEx delivery system. The devices killed two people and injured several others, and officials warned he could have left more bombs elsewhere that have yet to be found.
‘‘This is the culmination of three very long weeks for our community,’’ said Austin Police Chief Brian Manley, adding, ‘‘We don’t know where this suspect has spent his last 24 hours, and therefore, we still need to remain vigilant to ensure that no other packages or devices have been left through the community.’’
On Wednesday, FBI officials searched Conditt’s home for clues about what might have motivated the attacks as they advised Austin residents to remain wary. They took two of his roommates into custody for questioning — though they released one and said neither was under arrest.
Conditt attended Austin Community College from 2010 to 2012 but did not graduate, according to the school. He was a home-schooled student who described himself on a blog as “not that politically inclined’’ but expressed conservative views on issues like same-sex marriage and the death penalty. Friends and neighbors described him as a loner.
“Sometimes he was a very intense person,’’ said Jeremiah Jensen, a friend from the home-schooling community in Pflugerville. “He could sometimes get frustrated. There were times he could get angry over a misunderstanding.’’
Mark Roessler, 57, a neighbor, described Conditt as ‘‘quiet, introverted, polite and clean-cut.’’ He said he last saw Conditt about a week ago, when they both arrived home at the same time. ‘‘We didn’t make eye contact,’’ Roessler said. ‘‘In retrospect, he was certainly in the midst of all of this.’’
Eddie Harp, who has been friends with the Conditt family for 15 years, read a short statement to the media outside the Conditts’ home, saying:
‘‘I have a simple and heartfelt statement from the family. This will be their only statement. The family is grieved not only for their loss but also for the loss of those affected by these heinous actions. The family’s present focus is on dealing with their shock and loss and cooperating with the police investigation. If you are a praying person, please join us in praying for the families of all who have lost loved ones.’’
Law enforcement officials said they had no idea what might have triggered Conditt to carry out the bombings, but Governor Greg Abbott, a Republican, said he expected they would find a ‘‘treasure trove of information’’ inside Conditt’s home. Agents have found components that match materials used in the bombs in the suspect’s house, but not completed bombs, officials said. The Bureau of Alcohol, Tobacco, Firearms and Explosives has been able to reconstruct all the bombs. ‘‘We know it’s the same person who manufactured all of these,’’ said Deputy Assistant Director Fred Milanowski.
Conditt had been an enigma. After the first explosion killed Anthony House, 39, March 2, police were reluctant to call it a homicide. They at first explored a theory in which House might have been the unintended recipient of a bomb meant for a drug-dealing neighbor. When two more bombs went off 10 days later, they shifted gears. Over 350 law enforcement personnel descended on Austin.
They explored family ties between House and the second victim, Draylen Mason, 17, and whether the episodes might have been racially motivated. House’s stepfather and Mason’s grandfather were friends and prominent members of Austin’s African-American community. They wondered whether that made them targets.
The bombs continued.
A device activated with a trip wire injured two people, and investigators then discovered two packages that had been sent through FedEx. One exploded at a FedEx facility in Schertz, while the other was recovered from a facility in Austin.
The governor said officials first tied Conditt to the explosions by his cellphone, which they were able to detect was at the bombing sites.
FedEx surveillance footage would prove critical. It showed Conditt in a wig and gloves, and officers soon obtained a receipt for the disguise, Abbott said.
‘‘That proved to be the case,’’ Austin Mayor Steve Adler said.
Material from The New York Times was used in this report.
