NEW YORK – There's one video of a man walking to and from the scene of a bombing in a Manhattan's bustling Chelsea neighborhood. Another shows him minutes later planting another homemade explosive a few blocks away. A third has him in a backyard in New Jersey, apparently testing an incendiary device.
Prosecutors say the person captured on those incriminating videos and several others is Ahmad Khan Rahimi. The trove of digital evidence in Rahimi's ongoing federal trial is meant to provide airtight proof he was behind a 2016 attack that injured 30 people, but it also dramatically demonstrates the growing omnipresence of security cameras.
The Rahimi case relies "on video from security cameras in storefronts and businesses all over New Jersey and New York," Assistant U.S. Attorney Shawn Crowley said in opening statements. "You'll see video of the defendant in every stage of the attack."
Inspired by the "ring of steel" counterterrorism surveillance measures in London, the New York Police Department has led the security-video push in the last decade by blanketing the city with 13,000 of its own cameras, with access to an even higher number of private cameras.
Many of the NYPD cameras provide live feeds that can be monitored at command centers around the city. And the department has experimented with analytic software designed to alert police to unattended bags or to someone fitting the description of a suspect.
In the past, civil liberties groups have complained that the cameras are an invasion of privacy and pushed for protocols limiting how police use them. But over time, their proliferation has changed expectations about being watched.
"What we know is that there is no longer, or never was legally, any expectation of privacy on a public thoroughfare," said John DeCarlo, founder of The Center for Advanced Policing at the University of New Haven. "Because we all know that we're being recorded."
Experts say the deterrence impact of the cameras is limited because criminals tend to ignore them, making them mostly a valuable investigative tool for solving crimes.
When a bomber planted a homemade bomb on a train in London in September, for example, closed circuit TV footage provided vital clues that helped police arrest him within one day.
In the Middle Eastern emirate of Abu Dhabi, where security cameras are ubiquitous, police in 2014 were able use video footage to track a woman who stabbed an American school teacher to death in an upscale mall. An arrest was made within 48 hours.
Challenges for the police, particularly in ongoing cases, include sifting through tens of thousands of images quickly enough to find suspects before they attack again. Another possible pitfall is the often poor quality of many of the videos.
"Someone could be falsely identified because the quality wasn't good, or someone who may have done the crime but, say, lost 40 pounds and shaved before trial may not appear to be like the suspect on camera," said Dennis Jay Kenney, a professor at John Jay College of Criminal Justice. "If they aren't sharp, it can be a problem."
The issue of misidentification hasn't been raised so far in Rahimi's case.
The 29-year-old, who has pleaded not guilty to using a weapon of mass destruction and other charges, resembles the man in the videos, and his defense hasn't challenged assertions that they're the same person. Instead, his lawyers have sought to cast doubt on how the evidence was collected and asked the jury to keep an open mind.
Last week, jurors heard how after the bomb went off on the night of Sept. 17, 2016, the FBI and police immediately began collecting recordings from private cameras from various locations, including a residence for disabled people, a dental office and a small hotel that had its doors blown off by the explosion.
Prosecutors introduced footage showing a man believed to be Rahimi walking on the street with a backpack and two rolling duffle bags before sitting on the steps of a church just prior to the blast.
They also showed recordings of the defendant leaving his home at 5:30 a.m. on the morning of the attack; of his car exiting a New Jersey toll plaza near where he's accused of planting another bomb that also went off but didn't hurt anyone; of him returning to his home in Elizabeth, New Jersey, before taking a train to Manhattan that night; of him arriving at Penn Station en route to Chelsea; and of him leaving one of the bags with a pressure-cooker bomb that failed to detonate at a second location there.
Prosecutors say yet more footage from two days before the attack puts him his backyard for an apparent test run. As a pair of kittens played in the background, he's seen placing a black object on the lawn, lighting it and watching with a woman as flames shoot into the air.