She was the girlfriend of "Captain" Virgulino Ferreira da Silva, better known as Lampião (Portuguese pronunciation: [lɐ̃ˈpjɐ̃w], meaning "lantern" or "oil lamp"), the outlaw bandit leader.

The band, whose numbers varied between about a dozen up to a hundred, attacked small towns and farms in seven Brazilian states, fought pitched battles with paramilitary police, killed people and cattle, extorted money, kidnapped hostages for ransom, tortured, fire-branded, maimed, raped, and ransacked.

A number of cangaceiras joined the band over the many years of its existence, and it was usual for Lampião to personally attend any births.

[7] A number of recorded anecdotes indicate that Maria and the other women in the band sometimes moderated excesses of cruelty by intervening on behalf of victims threatened by Lampião and the other cangaceiros.

[8] On July 28, 1938, Lampião and his band were betrayed by one of his supporters, Joca Bernardes, and were ambushed in one of his hideouts, the Angicos farm, in the state of Sergipe, by a police troop armed with machine guns.

[9] The relationship of Maria Bonita and Lampião is firmly entrenched in Brazilian folk history, with a similar 'romance and violence' notoriety that Bonnie and Clyde achieved in the USA.