The serial bomber who terrorized Austin and put the Texas capital on high alert during the annual SXSW fest is dead, local police said today. But even with the confirmation that suspect Mark Anthony Conditt, 24, blew himself up this morning as police drew near, local authorities warned that still-undetonated explosives might have been planted.

“We still need to remain vigilant,” Austin Police Chief Brian Manley said.

At a press briefing in Round Rock today, Manley said police have not yet determined a motive for the six bombs that killed two people and injured five. Four of the explosives went off in Austin, the first on March 2, while a fifth detonated at a FedEx distribution center near San Antonio. An undetonated device was discovered in an Austin FedEx building.

Manley did not address speculation that race might be a motive; the two fatalities were African-American men, and Conditt was white.

A bomb scare last week led to the cancellation of a concert by the Roots at SXSW. A suspect was arrested in that case, and no bomb was found.

Conditt’s death, according to Manley, occurred after police traced his vehicle to a hotel north of Austin. After the suspect drove off pursued by SWAT teams, he drove his vehicle into a ditch off Interstate 35 and detonated a bomb, killing himself and slightly injuring a nearby officer.

NBC News reported exclusively today that police tracked the suspect through his online purchases of “foreign and exotic” batteries used to make the bombs.

Early this morning, President Donald Trump tweeted news of the suspect’s death and congratulated law enforcement: