Nicinha was a leader of the MAB fighting for the rights of the people displaced by the Jirau dam, denouncing the effects of the dam on fishing activity in the Madeira River. In 2011, the "ribeirinha" community of fisherfolk of Mutum Paraná, in the district of Porto Velho, upstream from the city of Porto Velho on the Madeira River, near Abuna on the border with Bolivia, was displaced because of flooding from the reservoir of the hydroelectric dam of Jirau, owned by Energia Sustentável do Brasil (ESBR). The community was in theory relocated in a place called Nova Mutum Paraná, a housing project for up to six thousand inhabitants, meant for people displaced. The relocation process did not go well - some of the houses were commercialized in favour of other people. Faced with a precarious situation, a group of families affected by the dam, occupied empty houses in Nova Mutum Paraná, in 2014. The settlement, that already suffered from water logging and lack of drinkable water, was submerged by a terrible flood along the whole Madeira River in 2014. In this context of adversities and injustices, Nilce de Souza Magalhães, better known as Nicinha, became a local leader of the MAB, the Brazilian movemement of "atingidos por barragens", those affected by dams. She had arrived in Porto Velho 50 years before, as a child from a seringueiro family in Acre. Together with two colleagues, Lurdilane Gomes da Silva (Ludma) and Iza Cristina Bello (Índia), they formed a Comissão de Defesa da Ocupação, and with help from the attorney general (Ministério Público) of the state of Rondônia, some local politicians and the MAB they confronted the firms controllings the dams, defending the rights of affected families. Over the years several claims were made, thanks to the leadership of fisher folks who participated in public hearings and demonstrations pointing out the serious impacts made on fishing activity in the Madeira River. The accusations led to two civil investigations carried out by the Federal and State Public Prosecution offices. One is regarding the non-implementation of the state’s program to support fishing activity. The second investigation of a more criminal nature points to the data manipulation in monitoring reports of fishing activity in the Madeira River.
The people making public such facts suffered from threats. On 7th January 2016, Nicinha disappeared; her corpse was found on 21 June in the lake formed by the Jirau dam, with bound hands and feet, tied to a stone, near the place where she had lived. It took more than six months to have DNA test done to confirm that the corpse belonged to Nicinha. Her family had to wait that long for her funeral. On 22 December 2016, a political act took place organized by MAB and many other organizations together with her family, in the chapel of Santo Antônio, on the Madeira River in Porto Velho. The funeral mass was celebrated by the Archbishop of Porto Velho, Dom Roque.
The jury trial of the two people accused of killing Nicinha, defendants Edione Pessoa da Silva and Leonardo Batista da Silva, was scheduled to take place on December 7th 2016, eleven months after the disappearance of Nicinha. However, the trial was adjourned due to the defense's request. The First Circuit Court of the region of Porto Velho rescheduled the jury trial due to the late attachment of an expert examination that was carried out one day before the jury trial was to take place. The law requires these attachments to be carried out at least 72 hours before trial takes place .
In the meanwhile, threats to her camarades Ludma and Índia intensified , a petition for protection to the programme of Human Rights (PPDDH) was made, according to the spokesman for MAB - Rondonia, João Marcos Dutra.  The MAB also points out that this is not an isolated crime.
Another 17 persons have been killed in the state of Rondonia in 2016 in environmental and land conflicts, apart from many other attempts at murder, threats, imprisoned peasants. Many land holdings are contested. The price of land is going up. One of the main cause of conflicts are infrastructures foreseen in IIRSA. There are plans for two more hydroelectic dams in the state, according to João Marcos Dutra. The state is a link in the chain with the south-centre of Brazil, with soy bean production to be sent to China through ports in the Pacific.