Hispanic teenagers began vanishing last winter in Brentwood, the working-class Long Island suburb 40 miles east of New York City.
Miguel Garcia-Moran, 15, disappeared in February. Oscar Acosta, 19, was reported missing in May. Jose Pena-Hernandez, 18, vanished in June.
If police noticed the pattern, they said nothing publicly until September, after two girls at Brentwood High School, ages 15 and 16, were beaten to death in what investigators suspect was an attack by members of the violent street gang MS-13.
Within a few weeks, the missing teens had all been found dead, their skeletal remains hidden in secluded areas of the hamlet, including the grounds of a partly abandoned state psychiatric center.
Now, some Hispanic advocates on Long Island are wondering why authorities didn't raise an alarm sooner about the string of disappearances. A spokesman for Suffolk County police says the information disclosed about each case varies, depending on the circumstances.
The county police commissioner isn't saying how many other teens might be missing.
"What's become clear to us over the last couple of months - and now we have evidence with the bodies being found - is the police department has not been taking these cases seriously," said Walter Barrientos, the leader of a Hispanic advocacy group.
Suffolk County police began pouring resources into the cases after the deaths of best friends Nisa Mickens and Kayla Cuevas, who were attacked in a residential neighborhood near an elementary school on Sept. 13.
Detectives suspect all are likely victims of the MS-13 gang, which has roots in El Salvador and outposts in communities across the U.S. The recent killing of a sixth person in Brentwood, a 34-year-old man, is also under investigation.
The crackdown on suspected gang members has resulted in about 35 arrests. Five alleged MS-13 members are in federal custody, expected to be charged under racketeering statutes.
But questions remain about what investigators did to try to find the missing teens months ago.
"They did not seem to do that much. ... They would never tell us anything," said Ana Arias, an aunt of Acosta. After he vanished, Arias said she and his mother went to local businesses and his school themselves seeking clues.
Justin Meyers, a Suffolk County police spokesman, said every missing-person case is fully investigated.
Meyers said the amount of information police release publicly about investigations varies, depending on whether foul play is indicated or whether the person appears to be a runaway.
"If you're approaching a case as a potential homicide or other criminal acts, the way you publicize and what you do publicly is going to be different," he said.
For more than a month, Suffolk County Police Commissioner Timothy Sini has refused to say whether other teens are missing in Brentwood.
Initially, he said the number wasn't available, but when pressed, he said police know but aren't comfortable releasing that information publicly.
"Giving too much detail could jeopardize certain cases," Sini told The Associated Press.
Just as he won't detail the number of missing teens, he also won't identify any of the three dozen suspects or say what they did. He did say the sweeps have resulted in a drop in violent crime. No one has been charged in any of the killings.
"We're out there shaking the trees, putting pressure on certain individuals, receiving information and acting on that information," Sini said.
MS-13 has been blamed on 30 other killings on Long Island alone since 2010.
The growing gang threat in the sprawling suburbs has been known for more than a decade, but efforts to stop the spread of violence have repeatedly faltered.
Critics say the police department was hampered in gathering intelligence when former Chief James Burke removed detectives from a federal gang task force from 2012 to 2013.
Sini, who became head of the department after Burke was arrested last year on charges he beat a burglary suspect in a precinct squad room, said he has worked to restore relationships between the department and FBI.
Barrientos, with the advocacy group, said the department also needs to reassure the Hispanic community.
It's important, he said, "that when children go missing in communities of color that they will be treated with the same urgency as when children go missing in other communities, where we see Amber Alerts or missing-person alerts go out within hours of a report being made."
Associated Press writer Claudia Torrens contributed to this report from New York.