While the 30-second clip starts well, things soon take a turn for the worse as Dean Wicks asks Linda Carter to consider what her husband will say if she tells him her baby might be his.
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A van crashes through Albert Square - but who's behind the wheel?
There’s also drama for DC Hayes, who is seen on the phone, stating: “I know you killed Lucy.”
Could we finally be getting some answers?
With many of the suspects' alibis not matching up, by New Year’s Day the list of suspects will be dramatically reduced.
The trailer also sees Ronnie Mitchell telling Nick Cotton to be careful, adding, “You don’t know who you’re dealing with.”, while another scene shows a van crashing through the Square.
The cast are currently gearing up for the show's 30th anniversary and on Friday morning, it was announced that a nostalgic, 'Gogglebox'-style mini-series will be aired exclusively on iPlayer.
'EastEnders': Who Killed Lucy Beale?
(01 of15)
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Lauren Branning Motive: BFFL Lucy has been rubbing belly buttons with Lauren's Dad Max. Enough said. (credit:BBC/Jack Barnes)
(02 of15)
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Billy MitchellMotive: Lucy hasn't very nice to poor Billy and we reckon he could finally snap and actually react to someone's mickey-taking for once. (credit:BBC/Nicky Johnston)
(03 of15)
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Lady DiMotive: This mutt is the shadiest newcomer of them all, just look at that face. There's darkness in those eyes, y'know. (credit:BBC/Jack Barnes)
(04 of15)
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Whitney DeanMotive: Newcomer Lee Carter chooses Lucy over Whitney, which in Soap world means she has more than enough of a reason to bump off her former pal. (credit:BBC/Kieron McCarron)
(05 of15)
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Danny PennantMotive: He bedded and then betrayed Lucy earlier in the year before dashing off - but could he come back and murder the youngster? We've seen more ridiculous things happen before. (credit:BBC/Jack Barnes)
(06 of15)
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Max Branning Motive: We all felt a bit queasy when it was revealed that Max was Lucy's secret lover and when we stopped feeling green we released that this HAS to make him suspect number one, surely? (credit:BBC/Jack Barnes)
(07 of15)
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Dot Cotton Motive: She's been lending a sympathetic ear to the residents of E20 for longer than we can remember. Everyone has to crack at some point. (credit:BBC/Jack Barnes)
(08 of15)
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Peter BealeMotive: He's been fed up of coming second to sister for a while now so it's definitely possible that Peter could finally reach breaking point and get rid of his sister. (credit:BBC/Nicky Johnston)
(09 of15)
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Phil Mitchell Motive: Has there ever been a murder that Phil isn't in some way related to? No, exactly. (credit:BBC/Nicky Johnston)
(10 of15)
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Cindy Williams (Beale)Motive: Cindy reveals a jaw-dropping secret about Lucy just before her shock death, perhaps the pair get involved in a fight with tragic consequences? (credit:BBC/Kieron McCarron)
(11 of15)
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Tracey Motive: Well, it's about time she got a proper story line, isn't it? Also, we've definitely seen her giving Lucy the evil eye occasionally. (credit:YouTube)
(12 of15)
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Ian BealeMotive: He's has to listen to Lucy's whining, deal with her problems and clear up her mess for the last 20 or so years. How many more trials can their father-daughter relationship take? (credit:BBC/Kieron McCarron)
(13 of15)
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Mick Carter Motive: Danny Dyer's characters always kill people. We've seen his films and reckon Danny must make sure there's a murder plot in store before signing up to any project. (credit:BBC/Ray Burmiston)
(14 of15)
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Aleks ShirovMotive: We've already seen his nasty side but we think there's more to this shady character, who is currently dating Roxy Mitchell. A definite one to watch. (credit:BBC/Jack Barnes)
(15 of15)
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Lee Carter Motive: The newest addition to the Square wasted no time in bedding Lucy and hooking up with Whitney. He's an ex-Army lad so he could probably take down the young business woman - and stay calm enough to clear up the mess afterwards. (credit:BBC/Nicky Johnston)