Image copyright AP Image caption Donald Trump listens as Michael Sexton speaks at the launch of the Trump University investment school in 2005

Court documents have revealed aggressive sales tactics employed by staff at Donald Trump's now defunct investment school.

Tips on how to push students to sign up for expensive courses were included in records released during a class-action lawsuit against Trump University.

Mr Trump, the presumptive Republican presidential nominee, has denied that the school misled students.

But Hillary Clinton described the venture as a "fraudulent scheme".

Mrs Clinton, who leads to race to be the Democratic nominee, said the former school was "used to prey upon those who could least afford it".

What is the case about?

The now defunct for profit school is at the centre of two class-action lawsuits in San Diego, California, alleging the company scammed students by failing to deliver on promises to impart Mr Trump's secrets of real estate success. Former students say they were misled by adverts claiming Mr Trump had "hand-picked" teachers and "overseen" the curriculum. The billionaire businessman continues to maintain the majority of his customers were satisfied with the real estate programme.

The documents were released following an order by US District Court Judge Gonzalo Curiel. The judge ruled that the files were in the public interest since Mr Trump had become "the front-runner in the Republican nomination in the 2016 presidential race".

Trump University was launched in 2004 as a business venture under the Trump brand, offering courses in entrepreneurship. The extent of Mr Trump's involvement in the scheme is a key point on contention.

What do the new documents show?

The trove of documents include manuals or "playbooks" for employees outlining how to "close the deal" and convince students to invest in business seminars that cost up to nearly $35,000 (£24,288).

The "playbooks" also advised sales staff on how to speak to reporters, how to dress and run Trump University events, as well as how to identify students with the most liquid assets.

The unsealed files also included depositions from executives describing how the operation worked.

They also included statements from employees describing the program a "scam". Former staff member Ronald Schnackenberg wrote that he left Trump University in 2007, citing the program used "misleading, fraudulent and dishonest" tactics.

The previously unseen testimony from Trump University executives goes some way to show Mr Trump's level of involvement in the school's marketing strategy. Michael Sexton, Trump University president, said in a 2012 deposition that Mr Trump offered "very good and substantive input" to the program's marketing materials.

What other lawsuits is Trump facing?

The documents were released in one of two class-action lawsuits in California against Trump University.

In a separate civil lawsuit in New York, Democratic Attorney General Eric Schneiderman has alleged that Trump University used deceptive practices and misled students about the support they would get. Mr Trump has denied any wrongdoing.

A judge has said the $40m case in New York could proceed to trial, but Mr Trump has appealed the ruling.

Why does it matter?

The San Diego case involving the released documents is expected to go to trial in late November, just weeks after the US presidential election. Mr Trump could be called to testify.

But he is not the only presidential candidate marred by legal dispute. His Democratic opponent, Mrs Clinton, remains embroiled in an investigation over her use of private email while serving as US secretary of state.