Police found a man and woman dead at a Premier Inn along with a mystery substance.
The pair were discovered unresponsive at the Mercury Gardens, Romford in East London at 12.43pm on Saturday afternoon, and were later pronounced dead, reports the Daily Mirror.
Metropolitan Police say they are treating the two deaths as unexpected, and probes have been launched to establish the circumstances surrounding the deaths.
Specialist officers attended the scene following reports of an unidentified substance.
Members of the London Ambulance Service and London Fire Brigade also attended the incident.
A Premier Inn spokesperson said: "Our thoughts are with the friends and family of these guests at this terribly sad time. Our team are assisting the police with their investigation."
The Metropolitan Police confirmed two people were pronounced dead at the scene.
A spokesperson for the force said: "Police were called at 12:43hrs on Saturday, 1 July after two people were found unresponsive at a hotel in Mercury Gardens, Romford.
"Officers attended along with the London Ambulance Service and the London Fire Brigade. A man and a woman were pronounced dead at the scene.
"Specialist officers also attended due to concerns about a substance that was found at the scene. The deaths are being treated as unexpected and further enquiries are taking place to establish the circumstances."
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