Her body was recovered from a stream in Tamworth.
The woman has been named locally as Keeley Bunker.
The bodies of a 32-year-old man and a 23-year-old woman were discovered at a house in Burton-on-Trent on Wednesday.
A teenage girl made it out of the Chasewater Reservoir safely.
She left a note saying she had “run out of fight” following six months of threats from her ex.
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The pair were arrested on suspicion of manslaughter by gross negligence
A 24-year-old woman and a 28-year-old man are in custody.
Driver is being quizzed by immigration enforcement officers.
'You put a lot of people at risk.'