Senior commanders have been killed on all sides of the Syrian war over the past five years. Generals in the Syrian army and Iran’s Revolutionary Guards Corps. Rebel chieftains, emirs of Daesh and veteran Hizbollah field operatives.

It is a dirty war, often fought at close quarters, and shifting loyalties create the conditions for treachery.

Mustafa Badreddine, Hizbollah’s operations chief, who died in mysterious circumstances last week, was without doubt one of the most key of all their combatants to expire prematurely on a Syrian battlefield. His death will not change the course of the bloody war, but it is a sign of how even the strongest players are struggling to maintain control, even of their own side.

Badreddine was one of a tiny handful of surviving members of the original band of Shia fighters first trained by the PLO in Lebanon in the late 1970s. They coalesced into what is now known as Hizbollah, the Iran-sponsored movement that has dominated Lebanese politics and become Tehran’s most efficient sub-contractor in its global terror campaign. Behind the scenes, he played a central role in its evolution from small, rag-tag militia to a mainstream party with a small but highly professional army.

Along with Imad Mughniyeh, Hizbollah’s military chief who was his cousin, brother-in-law and mentor, Badreddine planned some of the movement’s most spectacular operations, including the bombing of American and French embassies in the early 1980s and the assassination of Lebanese prime minister Rafiq Hariri in 2005.

Unlike Mughniyeh, who was killed in a joint Mossad-CIA hit in 2008, Badreddine, who assumed some of his cousin’s operational responsibilities, was less disciplined. He led two secret lives, one in the service of the cause, and a second one — under a variety of aliases — as a philandering playboy in Lebanon’s top resorts.

This death is different to previous assassinations in Syria. No footage has emerged of the scene and Hizbollah’s official explanation was a muddled and changing narrative. Ultimately, they blamed “radical Sunnis”, but no rebel group has claimed the credit for such a prestigious scalp. Israel, as in previous cases, has officially refused to either take responsibility or deny any involvement. Uncharacteristically, however, Israelis sources have quietly informed trusted journalists that it was not them this time. This alone, of course, does not remove Israel from the long list of potential suspects, but it is significant that Hizbollah has not blamed Israel, as it usually has done in the past.

All the signs point to something embarrassing in the circumstances of Badreddine’s death. The last few weeks have seen setbacks for the Iranian-led coalition fighting for Assad. Dozens of Shia fighters and Iranian officers were killed near Aleppo and unconfirmed reports emerged of a falling out between the commander of Iraq’s Qods Force, Kassem Suleimani, and Badreddine. Could Iran’s once trusty tool of violence finally outlived his use?