As is traditional, Israel maintained its traditional silence about the killing, neither confirming or denying its involvement.
Silence is one of Mossad’s most potent weapons, helping spread its mysterious and fearsome reputation around the Arab world.
Mugniyeh was the military leader of the Lebanon’s Shia movement Hezbollah and was wanted by more than a dozen countries, including the US, who had placed a €14 million bounty on his head.
However, the audacious nature of the assassination helped convince many experts it was carried out by Mossad.
The recent killing of Hamas commander Mahmoud al-Mabhouh in Dubai, with the use of five fake Irish passports, is just one in a long line of ruthless and daring killings carried out by the agency in countries all over the world.
Meaning “the Institute” in Hebrew, Mossad was formed in 1948, along with the state of Israel, to co-ordinate intelligence and conduct covert operations overseas. It’s original motto read: “By way of deception thou shalt make war.”
It reports directly to the prime minister who sanctions all executions.
Over the decades Mossad has earned a formidable reputation for it the ingenuity of its assassinations. Some of its most favoured methods of killing are said to have included strangling by piano wire, poisoning, a well-placed car bomb and electric shock.
In 1996, the agency reportedly killed a Hamas bomb-maker known as The Engineer by booby trapping his mobile phone and detonating it when he answered a call.
One of its most celebrated exploits involved the abduction of notorious Nazi war criminal Adolf Eichmann in Argentina in 1960. He was later tried and hanged in Israel.
A decade later, the agency was ordered by then Israeli prime minister Golda Meir to track down and kill the Palestine militants behind the killing of 11 Israeli athletes at the 1972 Munch Olympics.
The manhunt ended in a tragic blunder, however, when an innocent Moroccan waiter was killed in Norway in 1974 in a case of mistaken identity. The assassinations were later made famous in the Steven Spielberg movie Munich.
Much of what is known about Mossad has come from former disgruntled employees, who have revealed its methods and codenames including kidon (bayonet), the unit charged with assassinations.
The kidon are believed to have been responsible for the assassination of Canadian scientist Dr Gerald Bull in 1990.
Israel had attempted to secure the services of Dr Bull, at the time the world’s leading experts on gun-barrel ballistics, only for the scientist to offer his services to Saddam Hussein in designing the Project Babylon supergun for the Iraqi government.
A three-man team was sent to Brussels, where Dr Bull was living. He was shot five times in the head and neck at the front door of his apartment.
Diplomatic tensions, like the ones currently being seen between Israel and Ireland, are not new and have often been triggered by some of Mossad’s notable failures and bungled operations.
In 1997, during current Prime Minister Benjamin Netanyahu’s first term in office, one special operation went spectacularly wrong.
Israeli agents launched an effort to kill Khaled Meshaal, then a fundraiser for Hamas in Jordan.
Posing as Canadian tourists, Mossad agents injected poison into his ear. However, Meshaal’s life was saved when he was rushed to hospital before the poison could take full effect.
Israel was caused deep political embarrassment, when an outraged King Hussein of Jordan, backed up by US President Bill Clinton, demanded the Israeli government hand over the antidote for the poison.
The agents involved, who had been arrested, were later exchanged for an Israeli apology and the release of 20 prisoners including Hamas’s spiritual leader Sheikh Ahmad Yassin.
Meshaal is now Hamas’s Damascus based leader and is currently warning of retaliation for the recent killing in Dubai.
Yassin, a quadriplegic who was almost blind, was assassinated by an Israeli pilot of an helicopter gunship in 2004.
A stark example of just how active Mossad remain can be seen as recently as last November when a female passer-by reported to authorities a man attempting to plant a bomb under a car in the capital Tel-Aviv.
The man, who was arrested by police, turned out to be a Mossad agent taking part in a training operation using a fake bomb. Local police, it turns out, are not informed of any Mossad training operations.
Mossad’s website also has plenty of job opportunities available advertised on its website for the state’s spies of the future.
Israel’s wannabe spies are offered positions as researchers, code breakers and security offers in jobs which offer successful applicants the chance to work abroad in a “young and unconventional” environment.
Despite the lack of any official confirmation from Israel that last month’s Dubai hit was carried out by Mossad, most experts are in agreement about Israeli involvement.
The use of forged Irish, British and French passports has also severely strained diplomatic tension with Israel over the incident.
However, as has been pointed out, Israel have been down this road before and will likely go down it again.
And the Dubai assassination, will go down in history, as yet another in a long line of mysterious alleged Mossad hits.