BRENTWOOD, N.Y. (CBSNewYork) -- Suffolk County police are devoting all possible resources into the murders of two teenage girls, whose bodies were found blocks apart in Brentwood.
Security was extra tight Thursday at Brentwood High School following the deaths of 15-year-old Nisa Mickens and her best friend, 16-year-old Kayla Cuevas, CBS2's Sonia Rincon reported.
Police officers were in the building and the school also reintroduced metal detectors and handheld wands, while grief counselors were made available for students dealing with the heartbreak and fear.
A growing memorial marks the spot on Stahley Street where the body of Mickens was found Tuesday. Less than 24 hours later, her best friend's body was discovered a few blocks away in a wooded area off Ray Court.
The teens were severely beaten, but the medical examiner's office has yet to release any findings.
""These murders show a level of brutality that is close to unmatched," Suffolk County Police Commissioner Tim Sini told reporters, including WCBS 880's Mike Xirinachs.
Police believe the killings may be gang-related and they are going through the girls' social media accounts looking for clues. The teens were out celebrating Mickens' birthday. She would have turned 16 on Wednesday.
Mickens' mother left balloons Wednesday on the street where her daughter's body was found, and she pleaded for anyone with information to come forward.
"The only thing I want to tell everybody is please if you know something, say something," Elizabeth Alvarado said.
"She didn't deserve this. Neither one of them deserved this," grandfather, Robert Mickens said.
The grieving grandfather left a flower at the spot where her body was found -- the memorial began with a basketball that she wanted for her 16th birthday.
"These people don't realize what they're taking away from us. I'm supposed to walk my daughter down an aisle. They took that away. I'm supposed to have a Sweet 16 dance with my daughter. They took that away," father, Robert Mickens said.
Suffolk County Legislator Monica Martinez is an educator who knew both girls.
"I don't even know how to begin to even process what has happened here today," Martinez said.
"To whoever is responsible it is in your best interest to turn yourself in, because sooner or later you know what they say, what's done in the dark will come to light," community activist Lenny Tucker said.
A strong police presence is expected at a candlelight vigil that will be held at the school Friday evening.
In announcing a $5,000 reward for information leading to an arrest, Sini said detectives have been working with federal partners to find out who knows what.
"We've made a strategic subject list of known gang members in the area, we're going to be enhancing our presence here to target those individuals," Sini said.
He wouldn't comment on what may have led to the murders, but said there is very little doubt that gangs were involved.
"The nature of their injuries is an example, and I'll leave it at that," he said.
Injuries that include cut wounds. Both girls died of blunt force trauma.
Neighbors said the tragedy needs to be a wakeup call to crack down on gang violence.
"People are afraid of just leaving their homes. Unfortunately, it's escalating instead of going down. And because of that, people are just kind of adjusting their lives instead of doing something about it," Luis Alvarado said.
"They took over our streets. The police department needs to step back in and take their streets back, not let these gang members take over our streets," Betsy Oms said.
Anyone with information is asked to call the Homicide Squad at 631-852-6392 or anonymously to Crime Stoppers at 1-800-220-TIPS.
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