“We finish the race, and we do that because of who we are,” the president said to applause. “And that’s what the perpetrators of such senseless violence — these small, stunted individuals who would destroy instead of build and think somehow that makes them important — that’s what they don’t understand.”
“We will find you,” he warned those behind the attack.
Seven victims remained in critical condition. Killed were 8-year-old Martin Richard of Boston, 29-year-old restaurant manager Krystle Campbell of Medford, Mass., and Lu Lingzi, a 23-year-old Boston University graduate student from China.
Video and photos recovered in the investigation are being examined and enhanced by an FBI unit called the Operational Technologies Division, said Joe DiZinno, former director of the FBI lab in Quantico, Va.
Investigators are looking at video frame by frame — a laborious process, though one aided by far more sophisticated facial recognition technology than is commercially available, forensic specialists said.
“When you have something that is this high-profile, they are going to use every available resource that they have,” said former Miami federal prosecutor Melissa Damian Visconti.
The investigation will probably collect about a million hours of videotape from fixed security cameras and cellphones and cameras used by spectators, said Gene Grindstaff, a scientist at Intergraph Corp., a Huntsville, Ala., company that makes video analysis software used by the FBI and other law enforcement agencies.
But after years of investigating terrorist incidents and other crimes, the FBI is practiced at cataloging, categorizing and analyzing such evidence and will winnow it down dramatically, he said.
“Back in the days of 20 years ago, you were lucky if you had video and it was probably of poor quality and it took a tremendous amount of enhancement. Today you have a completely different issue,” Grindstaff said.