The family of Natalie Lewis-Hoyle, the daughter of the Commons deputy speaker Lindsay Hoyle, have appealed for information about her death.
Lewis-Hoyle, 28, was found unconscious at an address in Heybridge, near Maldon, Essex, on Friday morning.
Her mother, Miriam Lewis, a Maldon councillor, asked for anyone who had been contacted by Lewis-Hoyle on Thursday night to notify police.
She said her daughter’s phone was missing and may have been left on a train from London Liverpool Street to Ipswich.
She wrote on Facebook: “It is with unbearable sadness that I have to announce the sudden death of my beautiful, much-adored daughter Natalie.
“If Natty contacted you by phone, text, messenger or any other means on Thursday evening, 14 December, between 20.00 and midnight, please let me know through this page or contact A/Insp Jon Loudon at Essex police, incident no 158. Any little scrap of information may be more relevant than you imagine.
“Natalie is my only child, my mini-me. Please help me find out what happened to her in the hours before her death.”
Hoyle, the Labour MP for Chorley, said the family was “truly devastated”. He wrote on Twitter: “Our family will never be the same without our loving granddaughter, sister & aunty. Thank you for the kind support we’ve received, it is overwhelming.”
Fellow MPs, friends and strangers offered their condolences to Hoyle and his family. “What terribly sad news. Thoughts & prayers with you all,” wrote the Conservative MP Nicky Morgan.
The Chorley Labour party tweeted: “The thoughts and prayers of the entire Chorley CLP are with you and your family at this sad time,” and the local Conservative party office wrote: “How very sad; all our thoughts are with Cath [Hoyle’s wife], you and your family.”
Essex police said the death was not being treated as suspicious and a file would be prepared for the coroner.
