A brutal murder on Long Island has landed an alleged MS-13 gang member on the FBI's Ten Most Wanted Fugitives list.

As News 12 Long Island has reported, Vanessa Argueta, 19, and her 2-year-old son, Diego, were killed in Central Islip in 2010.

The FBI announced Wednesday that another MS-13 gang member, Juan Elias Garcia, has been added to its Ten Most Wanted Fugitives list in connection to the murders.

Federal prosecutors say he was among a group of men involved in the execution-style shootings of the 19-year-old and her son. Their bodies were found the next day in a wooded area in Central Islip.

Argueta and Garcia had been dating, but prosecutors say Garcia believed Argueta was associating with the rival "18th Street Gang."

Officials say they felt that if Garcia was added to the list, it would give the case international attention. News 12 Long Island has learned officials believe Garcia is in El Salvador or Honduras.

The other men involved in the killings, including reputed MS-13 member Heriberto Martinez, have been convicted in their deaths. Officials say Martinez ordered Argueta's son be killed so he would not grow up and seek revenge.

A $100,000 reward is being offered for information leading directly to Garcia's arrest. Anyone with information about his whereabouts is urged to call 1-800-CALL-FBI.