NEW documents from a former Cambridge Analytica insider reveal what a US elections watchdog claims was illegal coordination between Donald Trump’s 2016 presidential campaign and a billionaire-funded Political Action Committee (PAC).

The legal complaint touches on some of the same people involved in the current US presidential race and provides a detailed account alleging that Trump’s last campaign worked around election rules to co-ordinate behind the scenes with the PAC.

According to an updated complaint filed with the US Federal Election Commission (FEC) by the non-partisan Campaign Legal Centre, the now-defunct British data analytics firm violated election law by ignoring its own written firewall policy, blurring the lines between work created for Trump’s 2016 campaign and the Make America Number 1 super PAC.

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The complaint also alleges that Cambridge Analytica – which improperly acquired and used 87 million Facebook users’ profiles to predict their behaviour – had a shared project calendar for both entities, among other evidence.

Brendan Fischer, an attorney for the US government oversight group, whose new filing supplements a complaint originally filed four years ago, said: “The idea that this spending was at all independent is farcical, and these emails underscore that.

“Cambridge Analytica not only misused people’s personal data, but it was a conduit for the wealthy family that owned it to unlawfully support the Trump campaign in 2016.”

The super PAC created a plethora of “crooked Hillary” memes regarding the then-Democratic presidential candidate Hillary Clinton that circulated widely on social media, and was financed largely by conservative billionaire Robert Mercer, who also founded, owned and managed Cambridge Analytica.

Kellyanne Conway led an earlier incarnation of the PAC when it supported Texas senator Ted Cruz, before she resigned to advise Trump’s 2016 campaign, going on to become a senior White House adviser.

Under US federal law, a super PAC may raise and spend unlimited amounts of money, including from corporations and unions, to support candidates for federal office – but it is illegal for them to co-ordinate with political campaigns.

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The complaint alleges that Cambridge Analytica used the information it gained from working with Trump’s campaign to develop and target ads for the super PAC supporting his candidacy, “constituting unreported in-kind contributions to Donald J Trump for President, Inc in the form of coordinated communications”.

One September 2016 email it cites is from a Cambridge senior vice president, announcing that some of the PAC’s ads against Clinton were produced by “our production partner” Glittering Steel – which the former CEO of the Trump campaign, Steve Bannon, had a financial stake in.

Tim Murtaugh, the communications director for Trump’s re-election campaign, did not respond to repeated email and text messages seeking comment.

Kory Langhofer, an attorney for former Cambridge Analytica CEO Alexander Nix, said Nix had no knowledge of what is laid out in the complaint.

“While he was one of the executives there, he claims to be unaware of any coordination,” the attorney said.