The five officers are members of the Civil Police in the region known as Vale do Aco in the central part of Minas Gerais state, and are suspected of belonging to militia groups that operate in the area, the newspaper said Saturday.
Rodrigo Neto, who worked for the Vale do Aco newspaper, was slain March 9 at the door of his home, and at the time was specifically working on an investigative report about the activities of those militias.
Carvalho, from the same newspaper, was shot dead April 14 at a restaurant.
Minas Gerais Police Chief Cylton Brandao declined to make any comment on the police who have been arrested.
The press watchdog group Reporters Without Borders, known by the French initials RSF, has slammed the murders and demanded that Brazilian authorities investigate the possible involvement of police in these cases.
After Carvalho's death, RSF released a communique in which it also noted that the photographer was the fourth journalism professional murdered in Brazil to date in 2013.