In Coronation Street this week, viewers were left stunned as it was revealed that Theo Silverton’s killer is none other than Sarah Platt, but a new question has now been raised – did Lily Platt actually witness what happened?

Lily Platt appeared in the April 23 scenes, seen walking the cobbles upset after Jodie’s departure.

Now, a fresh fan theory is doing the rounds. It suggests she may have seen Sarah kill Theo and has been carrying that secret ever since.

Coronation Street’s Sarah killed Theo

Sarah’s carefully built world began to fall apart during Kit’s dinner party this week, after she cut her hand on broken glass. The incident triggered a traumatic flashback she had been desperately trying to suppress.

That flashback took viewers back to April 23, when Theo Silverton was killed following a confrontation up on scaffolding. In the moments leading up to his death, Sarah lost her temper during a heated exchange. She struck Theo with a pole, causing him to fall to the ground.

In a panic, she called Gary, who stepped in to help cover things up. He instructed her to clean herself up and make sure she was seen elsewhere to establish an alibi. He then disposed of the evidence.

Since then, Sarah has struggled to keep her secret buried. She eventually broke down and confiding in best friend Todd about what really happened. Todd was left horrified to discover Sarah killed Theo. Especially as Summer ended up going to prison for the crime.

Although Todd promised to keep Sarah’s secret, he made it clear he wanted nothing more to do with her going forward.

Coronation Street fan theory suspects Lily Platt knows who killed Theo

Lily Platt was also briefly seen in scenes during Carla and Lisa’s wedding day episode. And, it’s this appearance that has sparked a new theory among fans.

A fan theory now believes Lily may have actually witnessed Sarah killing Theo, meaning she could have been keeping quiet about it ever since.

Taking to Reddit, one fan theorised: “I actually wondered if Lily had seen Sarah killing Theo (considering Tina O’Brien said their were more twists to come with this), and was trying to contact Jodie to tell her, but this scene seemingly happens before Theo is killed since not long after we see Theo in his flat with Summer so I’m not sure.”

While the timing may not fully line up at first glance, it hasn’t stopped viewers speculating that Lily could have returned to the Street later and potentially seen something she shouldn’t have.

After all, if she was in the house earlier in the day, she may have crossed paths with Sarah during the attack. That still leaves open the possibility she was nearby when Theo met his tragic end, and could now be hiding what she knows.

Coronation Street usually airs Monday-Friday at 8.30pm on ITV.