Whether it was a senior commander in Hamas’s elite naval commando force who defected to Israel, as initially reported on Sunday, or merely a junior officer in the unit as was subsequently reported, the incident still represents a major Israeli intelligence coup.

Unconfirmed reports claimed the Hamas commander escaped aboard an Israeli military boat, carrying his laptop, surveillance equipment and “classified documents” the circulation of which would be harmful to Hamas. He had reportedly been cooperating with Israel since 2009.

Saudi news outlet Al Arabiya on Sunday identified the alleged defector, who reportedly escaped Gaza on Saturday accompanied by his brother, as Mohammed Omar Abu Ajwa.

Citing Hamas’s Interior Ministry and Palestinian media sources, Al Arabiya also reported that Hamas had arrested 16 of its own members, mostly from within the group’s military wing, the Izz ad-Din al-Qassam Brigades, on suspicion of spying for Israel.

The naval division is one of Hamas’s most classified and compartmentalized units. According to some assessments, it is the most important unit in Hamas’s military apparatus. The terrorist organization invests a great deal in finding, recruiting and training its members. Only the best of these candidates are designated for the naval commando unit, where they are said to undergo intense and grueling land- and sea-based training.

Hamas began forming the naval unit about a decade ago, upon the conclusion of the IDF’s “Operation Cast Lead” in Gaza. While the organization has always sought to carry out terrorist attacks via the sea, the Izz ad-Din al-Qassam Brigades realized that an elite, highly trained and well-armed naval force would greatly contribute to its deterrence. Such a unit could also help smuggle weapons into Gaza via the sea.

Hamas’s strategic decision to create and then invest considerable financial resources in the unit proved itself several years later, in 2014, during the IDF’s “Operation Protective Edge” in Gaza. In that war, armed Palestinian terrorists penetrated Israel’s maritime defenses, emerging undetected at Zikim Beach just north of Gaza with the aim of perpetrating a mass-casualty attack. Alert IDF spotters detected the Hamas force, which was wiped out. In the subsequent intelligence debriefing, however, it became apparent that the unit had made significant strides in terms of its operational capabilities.

It should also be noted that members of Hamas’s naval commando unit earn a starting salary most Gazans can only dream about: some $400-$500 per month—nearly five times the average salary in Gaza. Much of the unit’s training is geared toward targeting strategic Israeli infrastructure at sea, along with military and civilian vessels.

The unit’s members have also been tasked with developing the vast network of underground tunnels in Gaza belonging to Hamas and other armed terrorist groups. These efforts came to light in October 2017, when a tunnel belonging to Palestinian Islamic Jihad collapsed. Fourteen terrorists were buried alive, among them Hamas naval commandos.

The Islamist group has pledged “radical measures” against Palestinians who “collaborated” with Israel.

In recent years, Hamas has executed dozens of people accused of collaborating with Israel, typically without any judicial process.

This article first appeared in Israel Hayom.