Max's fling uncovered by mystery source

Max Branning will panic next week when he realises that somebody knows about his fling with Lucy Beale.

The worrying moment for Max (Jake Wood) comes as he continues to pursue Lucy, not wanting to lose her to newcomer Lee Carter (Danny-Boy Hatchard).
Feeling jealous, Max shows up uninvited to an open day that Lucy (Hetti Bywater) is holding at the Walford Common flats as part of her new lettings agency business.

Lucy isn't impressed by Max's behaviour, but it's not long before she gives into his charms.

Although Lucy later turns her attentions back to Lee, it seems that the damage has already been done when Max receives a shocking email.

The anonymous sender makes it clear that he or she knows Max's secret by including a picture of him and Lucy together earlier. Who has sent the message?
EastEnders airs these scenes on Tuesday, April 15 at 7.30pm on BBC One.