A woman who found a long-lost diary of an 11-year-old girl from 1946 has reunited it with her ancestors after spotting it in a street market – and it revealed the truth behind one family member's mysterious death.

Chelsey Brown, 28, from New York City, US, spotted the diary at a local flea market and decided to track down the owner.

Reading the entries, she discovered they were the musings of a child called Emily, who wrote about her school life and the untimely death of her uncle.

After his funeral, there were no more entries in the diary.

Chelsey found Emily’s surname and a 1946 date written in the journal, and input the information into MyHeritage – finding a name match in a 1940 census.

From there, she was able to find a public family tree where Emily’s brother was listed, and she contacted the owner of the tree to find out more about the family.

Chelsey, who regularly trawls charity shops and flea markets to find heirlooms that she can return, heard back from the owner of the tree – who was thrilled to hear about Emily’s diary.

“They responded with such excitement,” Chelsey told Jam Press.

“She was beyond overwhelmed and overjoyed,

“Emily was her father’s first cousin. Apparently, her father mentioned the one regret he had in life was not tracing that side of the family.

“She mentioned that Emily never had children.”

They were also aware of an “Uncle Joe” who had died at a young age – which, according to the diary, was a result of falling down the stairs and fracturing his skull.

In her response to Chelsey’s message, the ancestor said: “This is the most amazing surprise I've received since I began my family tree.

“I feel so very lucky to have been contacted by you Chelsey and feel blessed that this is yet another chance for me to find out more about my father’s birth-father’s family line.

“Thank you so much. You are the best and what you do is extraordinary.”

Chelsey shared the successful story on her Instagram, where she received more than 2,300 likes.

One person commented: “Wow Chelsey this is sooooo cool! The story you tell here about the diary and how her uncle passed is incredible.” [sic]

“Omg I couldn’t love this any more!!!” another user said.

Someone else added: “That’s so beautiful! I’m sure all the families are happy to be reunited with the items.”

“Omg this is SO cool!!” said one fan.

Other viewers described the story as “incredible” and lauded the thrifty woman for her efforts.

Chelsey added: “These heirlooms are so much more than just items – they can uncover family mysteries which is one of the most beautiful things about this.”

She describes her hobby as “beyond rewarding” and has returned hundreds of heirlooms to families across the US.