* Elected to the House of Commons last year, the 41-year-old represented a constituency in Yorkshire, northern England, for the main opposition Labour Party.
* She was previously an adviser to Sarah Brown and Glennys Kinnock, the wives of two former Labour Party leaders.
* She also worked with several charities, including Oxfam, Save the Children, the Bill and Melinda Gates Foundation and anti-slavery group The Freedom Fund.
* Cox, who chaired the Labour Women's Network, had made finding a solution to the Syrian civil war a top priority.
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* She was critical of Britain's reluctance to deepen its military involvement against Islamic State extremists but abstained in a vote on air strikes.
* She had recently campaigned for Britain to remain in the European Union ahead of the country's June 23 referendum.
* Cox initially backed Jeremy Corbyn for the Labour leadership but later said she regretted that and instead voted for one of his opponents, Liz Kendall.
* She graduated from Cambridge University in 1995. The first in her family to go to university.
* Married and with two children, Cox divided her time between a houseboat on the River Thames in London and a home in her electorate, Batley and Spen.
* She enjoyed running, cycling and mountaineering.