Wrath of God: The Israeli Response to the 1972 Munich Olympic Massacre is a narrative of the Mossad's operations against the Munich terrorists, from a site “intended to provide an overview of SOF, CT, Hostage Rescue and scores of issues related to Low Intensity Conflict.” I can't vouch for the accuracy of this narrative. But here is an echo:

Then there was the brief phone call Ben Berger [father of weightlifter David Berger] received a quarter century ago from an unidentified man, who also had not forgotten his son.
“We got them,” said a voice with an Israeli accent.
Berger immediately knew what that meant. With their government's blessing, Israeli hit squads had avenged the death of his son by killing two of the three remaining terrorists who were suspected of planning and carrying out the Munich massacre.

Andrea Levin of CAMERA provides some context for the Mossad's actions which the film ignores:

. . . . the assault at the Olympics was part of a worsening series of terrorist attacks against Israel in 1972. Lod Airport had been struck twice in May with 32 killed. Only days after the September 5 Munich atrocity, an Israeli official was shot in Brussels, and two weeks later a letter bomb killed an Israeli in London. . . . Yes, Israel's new counter-campaign was reprisal for the Munich murders, but it was aimed at fighting back against a broad terrorist threat. What the various teams dispatched by Israel sought to do was standard in its general goal: Shift the balance and force the adversary onto the defensive, disrupting operations, planning and command structure.

More context (originally from Stratfor; the original page isn't online anymore):

There is a model available from Israel’s operations following the Munich Olympic massacre in 1972. Although a number of Arab countries clearly supported the attackers, Israel did not attack those countries directly . . . . Rather, Israel accepted the amorphous nature of the attackers but nevertheless imposed on them a corporate identity – accepting them as an entity and holding the entire entity responsible, including all individuals regardless of what they knew, when they knew it or what they did. Israel launched a global attack on the entity, using its intelligence services and covert forces. The primary goal was destroying the operating capacity of what Israelis called ‘terrorist groups’ through killing key operatives and members of the command and control system. They did not strike in response to any particular act, nor did they constrain their actions by legalities.

German and Israeli media had retrospectives on the 30th anniversary of the massacre. SharkBlog posted a survey of the German media and translated some of the articles into English.

Imshin translated an Israeli documentary about the massacre, full of new behind-the-scenes information about the negotiations, bungled rescue attempts, attempts to warn various security services, German cover-up of same, and missed opportunities by the Israelis.

It seems the Germans are quite satisfied with the way they conducted the whole affair. Unlike some of the Israelis involved, such as Aharon Yariv, who accepts that Israel was partly responsible for the foul-up. Isn’t that just a typical Jewish thing to do, never letting yourself off easily? Bavarian Interior minister at the time, Bruno Merk, doesn’t display the same disposition for soul-searching. He puts the blame squarely on the Israeli security people.

So does Dr. Georg Wolf, deputy chief of the Munich police, doing a bad imitation of a Nazi in a WWII B-movie:

He starts off by blaming the Israelis for refusing to cave in to the terrorists’ demands.
Then he says: “Those responsible were those conducting the wars between Israel and Palestine, the Palestinians, I mean the Arabs.”
The interviewer is then heard saying: “As a host you are responsible for your guests.”
Wolf: “Yes, but as a host I expect my guests not to start a war in my home.”
Interviewer: “The Israelis did not start the war.”
Wolf: “That does not matter.”

The documentary also notes that only 8 years after Munich, “in the 1980 Moscow Olympics opening ceremony, Arafat could clearly be seen sitting in the VIP box right next to Brezhniev.”

Arafat was deeply implicated in the massacre:

According to Israeli media reports, Amin el-Hindi, who is currently the head of the Yasir Arafat's General Intelligence Service, masterminded the Munich massacre. At one point during the Israel-PLO negotiations in 1993, the Israeli negotiating team refused to take part in the talks until Hindi was dropped from the PLO delegation, because of his role in the Munich massacre.“ (New York Times, October 14, 1993)

In 2004:

The official newspaper of Yasir Arafat's Palestinian Authority has urged Arab regimes to boycott this summer's Olympic Games in Australia, because there will be a moment of silence at the start of the games in memory of the 11 Israeli athletes murdered by Arafat's PLO terrorists at the 1972 Munich Olympics. The call for a boycott of the Australia Olympics appeared in an editorial in Arafat's official newspaper, Al-Hayat Al-Jadida, on January 24, 2000.

Israel, which had observers on the scene in Munich, has never wavered in its insistence that Arafat was behind the killings. . . . Former Palestine Liberation Organization guerrilla Mohammed Oudeh, better known by the code name Abu Daoud, wrote in a book in 1999 that Arafat was briefed on plans for the Munich hostage-taking but added that the intent was never to kill the Israeli athletes. Israeli and American intelligence experts have long implicated Oudeh and the PLO in planning the attack that ultimately left 17 dead.

Abu Daoud
Lybia sheltered and paid at least one of the terrorists. From 1981:

Qadhdhafi provides terrorists with money, weapons, training, and false documents. The diplomatic pouches and secure cables of Libyan embassies afford an invaluable network for supplies and information. The Palestinians who killed eleven Israeli athletes at the 1972 Munich Olympics received their weapons through the Libyan diplomatic pouch (and those killed by the West German police received state funerals in Libya).

Libya provides monthly or annual payments to various organizations worldwide. It also collects a 6 percent tax on the income of Palestinians working in Libya, and transfers the money to the PLO-controlled Palestine National Fund. Libya has also made special grants to those responsible for a particular attack, or to a specific organization, in recognition of their actions. In their early 1970s, Qaddafi awarded Arafat $5 million in recognition of the massacre of Israel athletes carried out by Arafat’s men at the Munich Olympics.

The French as well as the Germans appeased the terrorists. This article is from 1999.

Terrorism has long been a source of friction between the United States and Europe. During the 1970s and 1980s, for example, it was not unusual for European governments to cut secret deals with terrorists. In exchange for the terrorists' agreement not to strike within these countries' borders or target their citizens, European authorities often turned a blind eye to activities that would otherwise have invited arrest and imprisonment. Consequently, extradition requests were frequently ignored. Captured terrorists often managed to escape from custody. Routine border-control procedures were conveniently ignored to allow terrorists to travel freely across international frontiers.

Perhaps the best-known instance of this behavior occurred in 1977 when French counterespionage agents arrested Muhammad Daoud Audeh - alias Abu Daoud - the reputed mastermind behind the 1972 Munich Olympics massacre, in which 11 Israeli athletes were seized and murdered by Palestinian terrorists. Both Israel and West Germany immediately requested Audeh's extradition. France, however, stonewalled, prevaricated, and then set him free, not wishing to incur the wrath of the Palestine Liberation Organization (PLO) and invite possible terrorist reprisal.

A National Security Council memorandum for September 11, 1972. Participating: President Nixon, Secretary of State William Rogers, Henry A. Kissinger, M/Gen. Alexander M. Haig, Jr.

The meeting was held for the purpose of discussing the situation in Munich which resulted in the death of 11 Israeli athletes together with Arab terrorists. . . .

Sharkblog expands on the speculation at the end of One Day in September, that maybe Germany did a deal with the Israelis and terrorists simultaneously. Read the comment by Moe Freedman.

”Terror, Inc“ traces the financing of terror groups by their own profitable businesses, both legal and illegal, to avoid the fickle support of state sponsors.
Part 1
Part 2