( CNN ) -- Thursday 's massacre of 11 students at a Brazilian school could have been even worse , were it not for the heroic actions of a military policeman , according to a statement from the Rio de Janeiro state governor 's office . Third Sgt . Marcio Alexandre Alves , 38 , and a colleague raced to the Municipal School Tasso da Silveira in Realengo after they were approached by a student two blocks away from the school , who asked them for help , the governor 's office said . Upon arriving at the school , Alves heard gunshots and quickly climbed to the second floor . There , he confronted the heavily armed gunman coming out of a classroom , keeping the suspect from ascending to the third floor , where there were more students , the statement said . Alves said he shot the gunman in the abdomen . When the suspect fell , he committed suicide by shooting himself in the head , according to the statement . At that point , Alves looked for a second suspect he had heard was in the building , but that information turned out to be unfounded , the governor 's office said . Alves , an 18-year veteran of police work , said seeing the slain children gave him a great feeling of sadness . `` Scenes that will not be easily erased from my memory . I have a son that age , '' Alves said . `` But it was also a sense of accomplishment . I wish I would 've arrived there sooner ( to save more children ) . Had I gotten there five minutes earlier , I could have avoided some deaths , '' the statement said . Brazil 's president has announced three days of national mourning . Beyond the 11 students killed , another 13 were injured , four of whom were in critical condition , Rio Health Secretary Sergio Cortes said . The Rio de Janeiro Civil Police released the names of nine of the massacred students to Agencia Brasil . the official state-run media . They are : . Karine Chagas de Oliveira , 14 . Rafael Pereira da Silva , 14 . Milena dos Santos Nascimento , 14 . Mariana Rocha de Souza , 12 . Atanazio Larissa Santos . Bianca Tavares Rocha , 13 . Luiza Paula da Silveira , 14 . Laryssa Silva Martins , 13 . Gessica Guedes Pereira . `` The greatest difficulty is the family 's pain . It is very hard to identify a son or a daughter in a situation like this , '' Cortes said . `` It 's a state of general commotion here , families , doctors , everyone . '' Several of the children will be buried Friday at locations and times still to be determined , Agencia Brasil reported . Municipal School Tasso da Silveira is in the northern Rio neighborhood of Realengo , a middle- and lower-middle-class area located between the Pedra Branca and Mendanha mountains . The school is now a crime scene , and will remain so for an undisclosed amount of time , police said . The government said the gunman was Wellington Menezes de Oliveira , 23 , a former student at the school . He was allowed to enter the school by saying he was there to obtain transcripts . According to CNN affiliate TV Record , Menezes de Oliveira entered the school in the morning armed with two handguns and began shooting at children and school personnel . He was firing `` indiscriminately , '' Agencia Brasil said . There were reports that he had left a letter behind that mentioned he had HIV , Agencia Brasil said . Other details from the letter were not immediately disclosed and the gunman 's motive remained unclear . The Rio government said they found no previous criminal record of Menezes de Oliveira . An amateur video posted on YouTube showed the police arriving at the school as onlookers watched from the front of the school . Repeated high-pitched screams can be heard as students begin sprinting out of the school in a line . One girl runs by with her shirt stained red around her abdomen . Another has what appears to be blood soaking her shoulder . The injured were transported to the Albert Schweitzer Hospital , where Agencia Brasil reported helicopters were waiting in an adjacent field , ready to transport the more seriously injured to other facilities . Police used some of those helicopters to move the victims , the government of Rio said . Rio de Janeiro 's Hematology Institute , which coordinates the distribution of blood for transfusions , put out a call via Twitter for donations to the hospital . Brazilian President Dilma Rousseff said she was `` shocked '' by the attack and had `` great concern '' about the incident . She said mass shootings were rare in Brazil . `` It 's uncharacteristic for our country to have this type of crime , '' she said in a speech . `` For that reason , I consider that all of us are united in rejecting this type of violence , especially against defenseless children . '' Rio 's governor , Sergio Cabral , called the gunman a `` psychopath . '' `` I agree that we have an obligation to give solidarity and support to the families of the young victims of this psychopath , '' he said . The school where the shooting happened is a public school with about 800 students . CNN 's Rafael Romo and journalists Luciani Gomes and Catalina Arica contributed to this report .
NEW : Sgt . Marco Alexandre Alves is being called a `` hero '' by Rio 's governor for confronting the gunman . NEW : Many of the slain students will be buried Friday , state-run media says . TL;DR The shooting happened at an elementary school in Brazil on Wednesday morning. He was a former student of the school , the government says .