The neutrinos were timed at their departure from CERN's giant underground lab near Geneva and again, after traveling 732 km (454 miles) through the Earth's crust, at their arrival at the Gran Sasso Laboratory in Italy.
To do the trip, the neutrinos should have taken 0.0024 seconds. Instead, the particles were recorded as hitting the detectors in Italy 0.00000006 seconds sooner than expected.
Knowing their findings would stir a storm, the OPERA team urged other physicists to carry out their own checks to corroborate or refute what had been seen.
ANALYSIS: FTL Neutrino Research 'Almost Certainly Wrong'
As part of this verification, an experiment called ICARUS at the Gran Sasso Laboratory took a separate look at the flight of seven neutrinos that had also been recorded by the OPERA team.
It used a new measuring technique, called a liquid argon time projection chamber.
"ICARUS measures the neutrino's velocity to be no faster than the speed of light," said Carlo Rubbia, a Nobel winner and spokesperson for the ICARUS project.