The hits came closer and closer together as New Year's Day approached. Every five or 10 minutes on a computer screen inside the Los Angeles County sheriff's Century station, a line graph spiked, a radar screen blipped and a target suddenly appeared on a map.
With each hit, the computerized system was pinpointing the location of another possible gunshot fired into the air in the Willowbrook neighborhood. Celebratory gunfire on New Year's morning has long been a problem in the Southland.
The sophisticated tracking system uses microphones placed around the neighborhood to detect powerful noises. And just past midnight, the ShotSpotter had shifted into overdrive.
From midnight to 12:30 a.m. Saturday morning, the system registered more than 700 hits in Willowbrook, where the ShotSpotter is undergoing a six-month trial before the department decides whether to buy it.
The problem? Many hits were undoubtedly triggered by other explosive noises such as the sounds of firecrackers.
Sheriff's officials believe that the system will eventually allow deputies to respond more quickly to possible crime scenes. For now, the department is using the ShotSpotter only to gather data, not to dispatch deputies. That won't happen for at least a couple of weeks, after the system's designers at Trilon Technology in Los Altos, Calif., have had a chance to work out the kinks, said Deputy Bob Killeen.
"The real test is in a few weeks, when all this has died down," he said. "Once we get it fine-tuned and our people are trained, we can actually use it for response."
Deputies at the Century station, which serves the Firestone, Willowbrook, Rancho Dominguez and Lynwood areas, agreed that celebratory gunfire seemed lighter this year, despite the fact that dispatchers there fielded 26 gunfire-related calls between midnight and 12:30 a.m. Only one injury report was called in, involving a Firestone man who was wounded in the shoulder by a falling bullet. That shot came from outside the ShotSpotter's area of detection.
Two other possible victims of guns shot into the air, a 12-year-old boy from South-Central Los Angeles and an off-duty sheriff's deputy in Temple City, suffered injuries that were not life-threatening, authorities said.
Friday night, Jason Dunham, who helped develop the ShotSpotter system for Trilon, monitored the computer while curious deputies peeked over his shoulder. The system has been used successfully by police in the Bay Area community of Redwood City to dramatically reduce New Year's Eve gunfire, Killeen said.
"People think you shoot a bullet in the air, and somehow it dissolves, or it floats down from space," Killeen said.
"But, no--it comes down, and it comes down hard. It goes through cars, it goes through roofs, it goes through heads."
Killeen hopes that the ShotSpotter will become an important law enforcement tool in combating all kinds of crime in which guns are used.
"Yes, we're trying to reduce the celebratory gunfire, but we're also trying to reduce the retaliatory gunfire, the drive-by shootings," he said.