Phil launches a desperate cover-up to protect his son Ben (Joshua Pascoe) in the coming days after discovering that the twisted teenager has killed Heather.
To Phil's relief, Andrew (Ricky Grover) soon becomes the police's prime suspect as they investigate the case.
McFadden told Inside Soap: "While the police are going after Andrew, they're not going after Ben. Phil does feel a mild amount of guilt, but Andrew's just collateral damage as far as he's concerned.
"Phil knows that Andrew will probably be set free - after all, he isn't actually a murderer - and as long as the spotlight is off Ben, everything's fine in his book."
Phil faces more pressure next week after trying to destroy Jay's (Jamie Borthwick) blue hooded top from the night of the murder - only for Patrick Trueman (Rudolph Walker) to find it half-burnt and hand it over to the police.
As all of the guests at Andrew's stag night wore the same hoodies, the authorities quickly realise that they have a new lead.
McFadden added: "The police are trying to find out which of the stag party attendees doesn't have their hoody any more. Phil ends up nicking Billy's and using it to replace Jay's. But in the process of helping out Jay, he implicates Billy."
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> Read more EastEnders spoilers and news
Watch Phil's EastEnders character trail in the video below: