"If the Arab youth was murdered because of nationalistic motives, then this is a horrible and horrendous act," said a statement from the family of one of the three killed teenagers.
The bodies of the three Jewish seminary students were found near the city of Hebron on Monday, two-and-a-half weeks after they were abducted.
Meanwhile, Israel retaliated to overnight rocket attacks.
from Gaza with 15 air strikes on the coastal strip mainly targeting suspected warehouses of arsenals.
Nine of the overnight rockets fired from Gaza hit Israeli territory, one of them striking a residential building in Sderot, while two others were intercepted by the Iron Dome anti-missile system above the Netivot of southern Israel.
Another rocket fired in the morning hit another house in Sderot, causing damage but no casualties.
Ten Palestinians were reportedly injured in Israeli air strikes.
"The Israeli Air Force attacked 15 terror sites in Gaza early Thursday morning," an Israel Defence Forces (IDF) official said.
"The targets included weapons manufacturing sites as well as training facilities,"he added.
Security sources here said that Israel's air attacks on Gaza should not be seen as part of any action it may be planning to take against Hamas for the kidnapping and murder of the three Israeli teenagers.
They were an immediate response to a wave of attacks from Gaza in which rockets and mortars were fired at southern Israel, they added.
