The grieving families of four young men found murdered in Central Islip last week in what Suffolk police believe was an MS-13 gang slaying pushed through their sorrow and shock Monday to focus on memorial services and burials.

A funeral Mass will be celebrated Wednesday morning at St. Joseph the Worker Roman Catholic Church for 16-year-old Justin Llivicura, according to the Rev. Martin Curtin, the pastor of the East Patchogue parish. Llivicura will be buried on Long Island, Curtin said.

William Tigre, the brother of victim Jorge Tigre of Bellport, said the family is planning a service for the 18-year-old later this week.

A service for Michael Lopez Banegas, 20, of Brentwood will be held from 6 p.m. to 9 p.m. Wednesday at Rose’s Funeral Home in Bay Shore, according to an employee at the facility.

Banegas’ family raised about $3,200 in two days on a GoFundMe account set up to cover the costs of transporting Banegas’ body to his native Honduras — about a third of the $10,000 needed to ship the remains.

A memorial service has not yet been scheduled for the fourth victim — Banegas’ cousin, Jefferson Villalobos, 20, of Pompano Beach, Florida. His family also is considering transporting his remains to Honduras, his mother, Francis Villalobos, told Newsday on Monday.

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The bodies of the four young men were found Wednesday in a Central Islip park, and authorities have said it appears the murders were the work of MS-13, a violent street gang with roots in El Salvador.

Suffolk police and the FBI are conducting a joint investigation into the murders, and Suffolk police have announced a $25,000 reward for information leading to the arrest of those responsible for the homicides. A spokesman for commissioner Timothy Sini, Justin Meyers, declined to comment on the investigation Monday.