BOSTON (AP) -- Moments after investigators went before television cameras to broadcast photos of two men in ball caps wanted for the Boston Marathon bombing, queries from viewers started cascading in -- 300,000 hits a minute that overwhelmed the FBI's website.
It marked a key turning point in a search that, for all the intensity of its first 72 hours, had failed to locate the suspects. While it's unclear how much the tips that resulted helped investigators zero in, experts say it instantly turned up already intense pressure on the two men to flee or almost certainly be recognized -- increasing the chances they'd make mistakes that would lead to them being exposed.
Late Friday, the manhunt at last reached an end in the Boston suburb of Watertown, when police cornered 19-year-old suspect Dzhokhar Tsarnaev, hunkered down inside a blood-spattered boat parked in the backyard of a three-bedroom house.
The decision that led to their quarry ----one that investigators had to weigh carefully.
"It was a good decision to put this out to the public ... and this would have been a calculated risk. But the intent would have been to get these guys to change their pattern" of behavior, said Martin Reardon, who spent 21 years as an FBI agent and is now a vice president of security consultant The Soufan Group.
Releasing the photos greatly increased the odds the two men would be recognized and turned in, even as it significantly upped the chances they would try to vanish or commit more mayhem -- exactly the scenario that played out.
"Clearly these guys were reacting and responding exactly as (law enforcement) predicted," said Robert Taylor, a criminologist at the University of Texas at Dallas who studies terrorism. "If you saw your face on TV and everywhere else as associated with the bombing ... you would act irrationally, and that's exactly what they did."
After three days without being able to identify a suspect by name, investigators clearly made the decision to release the photos Thursday on the belief that, without doing so, the suspects might remain at large for weeks or months, with the chance to flee or to act again, said David Weinstein, a former federal prosecutor in Miami.
So with photos in hand, investigators made a choice deemed both necessary and prudent.