The video sparked outrage: 15-year-old Lesandro "Junior" Guzman-Feliz dragged out of a Bronx bodega and butchered by six alleged gang members.
While the neighborhood cried out for justice, the tips began rolling in at police headquarters.
"We knew right away that we were going to get a lot of information," said NYPD Lt. Marc Moreno. "Because the facial characteristics of the perpetrators were so good."
Moreno heads the NYPD's Crime Stoppers Unit. He oversees a program offering cash rewards for information leading to arrests and indictments.
"As a detective, you can go out and knock on multiple doors, but people who witness the crime may not be comfortable talking to you at the scene," said Moreno.
Moreno said the unit's tip line received hundreds of calls once surveillance video of Lesandro's killing was released.
From those calls were 98 tips of value, information detectives considered important, were sent to the 48th Precinct Detective Squad. Tipsters also passed along cellphone videos.
"A lot of that video was instrumental in piecing together the details of that crime for the 48th Precinct," said Moreno. "When you put that video together with the witness statements that they had, it really helped them come down to a conclusion of exactly what happened."
So far, police have arrested eight people, but the investigation continues.
The unit says it has helped solve 1,500 murders in 35 years.
$130,000 was paid to 138 tipsters last year alone. Funding is provided by the New York City Police Foundation, a nonprofit that finances NYPD programs that don't fit in the city's budget.
"We don't know any of the people who gave us these tips that led to the rewards, but we're forever grateful," said Gregg Roberts, the executive director of the foundation.
Anonymity is key. Each caller is assigned an ID number. When a tip leads to a reward, the bounty is sent to a specific bank and the tipster presents the number to collect it. No name is needed, and no calls are traced to learn the tipster's ID.
"There are people out there, scared to talk to the police, that know information about a particular crime," said NYPD Det. Hector Nieves. "We encourage them to call Crime Stoppers."
Anyone with information about Lesandro's killing or any other crime is asked to call that anonymous Crime Stoppers hotline at 1-800-577-8477, or text CRIMES and then enter TIP577, or visit www.nypdcrimestoppers.com