Pascal Kabungulu Kibembi was executive secretary of Heritiers de la Justice, a Christian Aid partner founded in 1991 to challenge the brutal excesses of the then Congolese President Mobutu's dictatorship.
Mr Kibembi, whose uncompromising campaigning put him in the line of fire, was shot in the early hours of Sunday morning by three men who broke into his home in Bukavu in eastern DRC.
His commitment to reporting human rights abuses, particularly by political and military authorities, came with a huge risk. In 2003 he was issued with a death threat by the local military and forced into hiding.
Mr Kibembi documented and denounced human rights abuses, including killings, arbitrary arrests, rapes, looting, torture and kidnappings that continue to take place in the war-torn DRC.
In 2002, he accompanied Christian Aid on a visit to see Tony Blair and Sir Bob Geldof.
He told them it was essential that records of human rights violations be kept so that the truth could one day be told.
'We must keep the evidence,' he told the Prime Minister. 'One day when the war ends we must have a war crimes tribunal so that the people who committed these crimes are held responsible. Without these records this will be impossible.'
Paul Valentin, Christian Aid's international director, said Pascal Kibembi's death was a blow to people campaigning for an end to the on-going violence in DRC.
'It is with deep shock and sadness that we learnt of Pascal Kibembi's assassination,' he said.
'Pascal was well known to Christian Aid as a deeply committed human rights champion who kept our, and many other organisations and governments' attention focused on the situation in eastern DRC.'
Christian Aid would like to see the Congolese authorities undertake a full investigation and bring the perpetrators to justice.