EastEnders’ Zack Hudson (James Farrar) issued Teddy Mitchell (Roland Manookian) a dark threat on Thursday, as the mystery around Harry Mitchell’s (Elijah Holloway) missing ex-girlfriend Shireen deepened.

Following their arrival in Albert Square last year, it was revealed that Harry’s ex had disappeared, with many people believing he was somehow involved.

After getting into a feud with Walford copper Jack Branning (Scott Maslen), Harry was arrested. However, his mum Nicola Mitchell (Laura Doddington) came to the rescue with a false alibi from the night Shireen went missing.

But earlier this week, Nicola dropped the bombshell on Zack that her ex-husband Teddy had killed her.

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It was seemingly another ploy of Nicola’s to stop Zack from revealing to Teddy that he is actually their teenage son Barney Mitchell’s (Lewis Bridgeman) real father.

However, Nicola’s claims were shed in a new light in Thursday’s episode, as other people tried to convince Zack of Teddy’s guilt and the danger he could pose him.

After being dumped by Teddy earlier this week when her steamy liaison with Grant Mitchell (Ross Kemp) came to light, Sharon Watts (Letitia Dean) did some digging of her own into Shireen’s case.

Finding evidence that stacked up against Teddy, she pleaded with brother Zack to keep quiet about Barney’s paternity, fearing Teddy would kill him too.

Zack remained unafraid but was forced to reconsider his approach after some words of warning from Penny Branning (Kitty Castledine).

Penny had her own run-in with the extended Mitchell clan last year, having done some of her own investigations into Shireen’s disappearance while she was dating Harry.

Admitting to Zack she had been terrified about what the Mitchells were capable of, she told her pal to steer well clear.

As Zack then bumped into Teddy at the Albert, the two men squared up to one another once again following their fisticuffs on Wednesday.

While Zack stopped short of spilling his paternity secret, he then ominously warned his rival: ‘It will keep…’

But is Zack in danger? And was Teddy really behind Shireen’s disappearance?

Fans will start to get some answers next week, when Shireen’s brother turns up in Walford, seeking out Harry…