Story highlights Four students found dead last month had all attended the same Long Island high school

Suffolk Police have said they are looking into possible gang involvement

(CNN) In the span of 11 days last month, the bodies of four teenagers -- including the skeletal remains of two victims missing for months -- were found in yards and wooded areas of a suburban Long Island town.

Suffolk County Police haven't announced any arrests in the mysterious slayings, which have the community on edge.

Police Commissioner Timothy Sini said Monday there is an indication of "gang involvement" in all four deaths, but he declined to elaborate.

Nisa Mickens, 15; Kayla Cuevas, 16; Oscar Acosta, 19, and Miguel Garcia-Moran, 15, had attended the same high school in Brentwood, a working-class community about 45 miles east of New York City. Mickens and Cuevas were beaten to death, CNN affiliate News 12 Long Island reported. Acosta and Garcia-Moran also were victims of assault, according to Sini.

The first sign of tragedy came when a passerby found Mickens' body on a Brentwood street on September 13, the eve of her 16th birthday, according to Sini. The following day, the body of 16-year-old Cuevas, who was Mickens' best friend, was discovered in the backyard of a nearby home after the two had gone for a walk the night before, News 12 reported.

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