HONG KONG — In 2012, with help from Goldman Sachs, a Malaysian sovereign wealth fund called 1Malaysia Development Berhad sold $3.5 billion worth of bonds backed by an Abu Dhabi government fund to help it purchase power plants.
But behind the scenes, American officials have claimed, nearly $1.45 billion was illegally redirected to Swiss bank accounts and ultimately into the hands of some of the people involved in the deal.
That deal is now part of an international investigation into the Malaysian fund, known as 1MDB, that has plagued Najib Razak, the prime minister of Malaysia. A civil complaint filed by Justice Department officials in the United States said that some of the funds landed in the hands of Mr. Najib’s friends and associates as well as officials and executives from Abu Dhabi’s sovereign wealth fund.
On Monday, Malaysia and Abu Dhabi moved to clean up one part of the scandal: who would pay back investors who bought the bonds.
The Abu Dhabi fund, the International Petroleum Investment Company, said in a stock exchange announcement in London that Malaysia’s finance ministry and 1MDB had agreed to pay $1.2 billion to the Abu Dhabi fund by the end of the year as part of an agreement overseen by an arbitration panel in London.
The settlement also calls for the Malaysian side to take over all interest and principal payments on the two 2012 1MDB bonds, which charge interest rates of nearly 6 percent and are due for full repayment by 2022.
The deal on Monday is a significant step forward in cleaning up the financial mess related to 1MDB. One year ago, 1MDB defaulted on the bonds, setting off a dispute between the two countries over who would pick up the tab. Last year, the Abu Dhabi fund and its subsidiary, Aabar Investments PJS, said they were taking both 1MDB and Malaysia’s finance ministry to arbitration in London, seeking $6.5 billion.
But 1MDB isn’t out of the woods yet. The fund remains the subject of investigations in Singapore, Switzerland, the United States and other jurisdictions. American officials are still seeking to recoup $1 billion they say was ultimately spent in the United States on purchases like luxury homes in Manhattan and Los Angeles and expensive paintings by Picasso and Monet, and on financing for the Hollywood movie “The Wolf of Wall Street.”
In Singapore, officials have closed branches of two Swiss banks and jailed a number of private bankers in relation to the case.
Officials in several jurisdictions have highlighted transfers involving Low Taek Jho, also known as Jho Low, a young Malaysian financier who partied with the likes of Paris Hilton. American officials say Mr. Low played a crucial role in laundering hundreds of millions of dollars from 1MDB into the United States.
Mr. Low and Mr. Najib have previously denied wrongdoing.
“The government is pleased that IPIC and 1MDB have resolved their differences in an amicable manner,” Tengku Sariffuddin, the press secretary to Mr. Najib, said in a written statement on Monday.
“These significant events represent the continued positive progress made by 1MDB,” he added.
Goldman Sachs — which, according to American officials, received fees as high as 11 percent of the proceeds from the two 1MDB bond sales, which were code-named Magnolia and Maximus — put its main banker on the 1MDB account, Tim Leissner, on leave last year. Mr. Leissner has since left the bank, and in March, Singapore regulators banned him from dealing in securities in the city for 10 years. Goldman has said it is cooperating with the investigations.
Abu Dhabi dismissed the head of IPIC, Khadem al-Qubaisi, in 2015. That year, it also dismissed Mohamed Ahmed Badawy Al-Husseiny as the chief executive of one of IPIC’s subsidiaries, Aabar Investments PJS, which was tied to the 1MDB deals. Both men were identified by American officials in their civil lawsuit in July.
IPIC did not return phone calls and a fax to its headquarters in Abu Dhabi on Monday, and attempts to reach Mr. Qubaisi through his former employer were unsuccessful.