Desperate to check on her elderly mother amid the chaos of Sudan's war, Amal Hassan left her family home in the capital Khartoum on May 30.She has yet to return.Her husband and three children in Omdurman -- part of greater Khartoum -- are among the hundreds of Sudanese families desperate for news of loved ones who have disappeared.At least 3,900 people have been killed since war broke out in mid-April between the army and the paramilitary Rapid Support Forces (RSF).