HAUPPAUGE, N.Y. (CBSNewYork) — Suffolk County police believe gang violence is behind a recent spike in homicides throughout the county.

According to police statistics, there have been 34 slayings in Suffolk County so far this year — up 36 percent from 25 slayings reported last year, WCBS 880’s Mike Xirinachs reported.

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Police officials have connected 13 killings this year to gang violence, with eight of those coming out of the Brentwood section.

In October, the skeletal remains of an 18-year-old, who police said was a known MS-13 gang member, were found in a wooded area near the Pilgrim Psychiatric Center.

The discovery was made days after another man was found beaten to death in what police believe was a gang-related incident.

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In September, four Brentwood High School students were found dead. All are suspected victims of gang violence.

Nisa Mickens, Kayla Cuevas

The bodies of Nisa Mickens and Kayla Cuevas were found in Brentwood on Wednesday, Sept. 14, 2016. (Credit: CBS2)

On Sept. 13, the day before her 16th birthday, Nisa Mickens’ brutally beaten body was found on a tree-lined street in Brentwood. A day later, the beaten body of her lifelong friend, 16-year-old Kayla Cuevas, was discovered in the wooded backyard of a nearby home.

Days later, police discovered the skeletal remains of 19-year-old Oscar Acosta and 15-year-old Miguel Garcia-Moran in a remote industrial area of the town. Acosta had been missing since May, and Garcia-Moran vanished in February.

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In neighboring Nassau County, homicides are down, with 20 reported incidents compared to 24 reported last year.