Friends of the peaceful protester, Mohammad Mattar, have started a social media campaign asking people to change their profile pictures to shades of blue in solidarity with protesters' pro-democracy struggle in Sudan.
Mattar shot and killed by Sudan's Rapid Support Forces (RSF). His friend's say his favourite colour was blue and it was the colour he had on his profile pictures the day he died.
A "blue wave" has washed over social media platforms. The colour blue has come to symbolises all who have lost their lives during the uprising.