Prime Minister Najib Abdul Razak was not named in the lawsuits filed yesterday by the United States Department of Justice because the complaints were only to seize assets, said US attorney general Loretta E Lynch.

Asked if there was an arrangement not to name Najib, she said: "Our agreement is only to draft the complaint as we do in civil forfeiture matters and it's a complaint against the actual money or assets as opposed to against an individual.

"We don't have announcements on anyone not named so far.

"So this will be a complaint that seeks to restrain and forfeit the specific assets mentioned," she said at a Department of Justice press conference in Washington DC, streamed live online.

The complaints filed in Los Angeles named Najib's stepson Riza Aziz, their family friend and businessman Jho Low and two Abu Dhabi government officials.

The lawsuits also made references to one “Malaysian Official 1".

Asked why this person was not named, Lynch said a civil complaint traces the movement of the assets and would only "allege what we need to allege to obtain what we need to obtain".

She said the ultimate goal is to return the funds believed to have been misappropriated, an amount of about US$3 billion, to the people of Malaysia.

However, some of these funds have "dissipated" including through paying of gambling debts and "lifestyle expenses".

This is why the civil forfeiture had to be filed immediately despite the ongoing investigations, she explained.

Lynch said further delays could mean assets being transferred to other parties, making it more difficult to seize.

"We are able to trace US$1 billion which has gone through the US financial system and we are able to locate specific assets in the US and overseas.

"A lot of funds have dissipated through gambling expenses (and) lifestyle expenses. A lot of the funds have dissipated," she added.

Lynch said the forfeiture is the largest ever to be made by the US government in combating kleptocracy.

"We want to make clear to corrupt officials around the world that we will be relentless in our efforts to deny them the proceeds of this crime," she stressed.

She said the action to seize assets purchased using what investigators believe are 1MDB funds is helping the government of Malaysia, which remains an ally to the US, especially in counter-terrorism efforts.

"This effort ultimately benefits the country," she added.

Among assets the US Department of Justice hopes to seize are proceeds from the blockbuster film 'The Wolf of Wall Street' going to Red Granite Pictures, a motion picture firm owned by Najib's stepson.

Malaysiakini has contacted the Prime Minister's Office for comment.

Najib has previously been cleared of wrongdoing in the RM2.6 billion donation case and RM42 million funds from state fund SRC International found in his bank account.

He was not investigated over 1MDB, but maintained he never used public funds for personal gain.

He ordered a public audit of 1MDB following public pressure, including to determne if 1MDB funds were used to make a film.

However, the audit report is classified as confidential under the Official Secrets Act.

Read the US Department of Justice’s lawsuits below:

Editor's note: If you are viewing this on the Malaysiakini app, please click here to read the 136-page court document filed by the US Department of Justice.