Felix Kjellberg, more commonly known as PewDiePie, made himself known to those of us not entirely au fait with the world of YouTube vloggers last week, after Disney-owned Maker Studios took the decision to sever ties with the star following a report that he had posted several videos featuring anti-Semitic imagery.

The Swede is YouTube’s most popular personality with more than 53 million subscribers and is reported to earn $15 million a year from his work as PewDiePie, as per Forbes’ calculations. With figures like that, brands probably assumed him to be a fairly safe bet as an influencer to get on board with. Last week’s revelations showed him to be anything but.

The incident proved how important it is, then, that brands do their research on influencers before entering into a partnership with them. The Wall Street Journal investigation which unearthed Kjellberg’s supposed transgressions dates back to August 2016 – Maker Studios had plenty of opportunity to take action before the WSJ got going with its investigation and save itself the embarrassment of having to recoil from the partnership.

YouTube also took the decision to distance itself from Kjellberg, cancelling the release of ‘Scare PewDiePie Season 2’, a sequel to an original YouTube series, and dropping PewDiePie from Google Preferred, a program that offers advertisers access to its most popular channels.

Meanwhile, Nissan, which paid him for a promotional video posted in December, said it would not work with him again.

In response to the allegations, Kjellberg apologised for the posts, but suggested that it was a matter of humour having gone awry rather than anything malicious.

However, no apology will be enough for brands not to give Kjellberg a wide berth – at least in the short term anyway, Kjellberg will be out-of-bounds for brands looking to profit from some influencer marketing.

It’s hard to feel too sorry for Kjellberg in all this, though – his popularity and his earnings are unlikely to have taken too much of a hit.

Anyway, we’re more concerned with the matter from a brand perspective. That is, what brands can do to avoid a ‘PewDiePie situation’.

Influencer marketing is only going to get bigger. I went on record saying it will own 2017; the PewDiePie incident has proven me right already (he says, unabashedly), for it shows how brands are so keen to leverage the popularity of influencers that they are willing to overlook signs suggesting that the relationship could at some point turn sour.

Brands can’t afford to leave themselves so open. Vetting influencers needs to become more formalised and thorough. Here are four ways to ensure you’re entering into a relationship with an influencer that isn’t going to go south:

1. Stick with those who play by the rules

A study by influencer agency Takumi from last year suggested that influencers are readily flouting the UK’s rules on non-broadcast ads, which the Advertising Standards Authority (ASA) enforces. The rules state that sponsored posts from influencers should be labelled with a hashtag, like #ad or #spon, but often posts are being published by influencers without anything to signify they are being paid for the content.

While the ASA has been lenient on punishments so far, that could change as influencer marketing becomes more commonplace. Brands, then, should filter out those influencers who choose not to play by the rules. Even if formal punishments are not introduced, the consumers viewing the posts will probably see through any unmarked sponsored posts, which threatens to destroy the main draw of influencers: their authenticity.

2. Carry out a content audit

A time-consuming endeavour it may be, but it’s well worth carrying out an audit of an influencer’s content to make sure there’s nothing that’s going to come back to haunt you (and the influencer) later down the line.

If your food brand is opposed to the term ‘clean eating’, for example, there is sense to trawling through an influencer’s post to make sure there’s no mention of said phrase.

For some influencers – those with hundreds of hours of content – you’re not going to be able to do a complete content audit. Cover enough to be able to draw some firm conclusions.

3. Make the most of tools

It can be quite hard to find relevant influencers without spending a long time trawling through hundreds of Instagram accounts. For the sake of our sanity, there are tools like Whalar which can be used to find influencers who will truly amplify your content to full effect.

With Whalar, you can search a database of influencers by topic, location, engagement, rates, etc.–all of whom are keen to collaborate with relevant brands.

4. Get an agency to carry out due diligence

If you haven’t got the necessary time or resources to carry out due diligence on an influencer or a set of relevant influencers, consider getting an agency to do the groundwork for you.

It’s either that or you inevitably cut corners in your own due diligence and run the risk of entering into a relationship with an influencer who isn’t suited to your brand – or worse, proves a liability for your brand.

You’ve been warned! This isn’t the last time we’ll see a brand make a misstep with influencer marketing, mark my words.