Four adults were also hurt in the accident, which occurred around 3:15 p.m. Saturday on eastbound Route 40. But authorities were still working Sunday to determine what caused the crash involving a Hummer H2 and a Ford Taurus wagon.
A 13-year-old Pomona boy and a 7-year-old Williamstown girl - both passengers in the wagon -were pronounced dead at the scene. Another passenger, the boy's 11-year-old brother, died Sunday afternoon at Cooper University Hospital in Camden.
Two other passengers - the boys' 9-year-old brother and the girl's 5-year-old sister - remained hospitalized Sunday night.
Both drivers and two other adults in the wagon were treated for undisclosed injuries, none of which were considered life-threatening.