The parents were business owners whose holdings included a coffee plantation, a warehouse, a processing plant for coffee and rice, cattle, and a butcher shop. The couple had only one son, who died shortly after birth. All four sisters completed their primary and secondary education in one of the most prestigious private boarding school in the Dominican Republic, El Colegio de la Imaculada, a Catholic school in the town of La Vega.
Maria Teresa had completed her degree in land surveying at the University of Santo Domingo in 1957.
Realizing that creating a resistance movement required recruitment and orga-nization of other like-minded citizens, Minerva and her husband organized El Movimiento 14 de Junio, a name derived from a group of Dominican exiles whose invasion to overthrow the government was set for June 14,1959. The initial group numbered 13 and very quickly grew to include some of the most prominent members of the community. With the expansion of the movement, secrecy became more vulnerable, and soon the secret military police uncovered the movement's activities, and arrested many of its leaders, including Minerva and Maria Teresa and their husbands, Manuel and Leandro, in early January 1960. Patria's husband, Pedro González, escaped arrest by going into hiding.
The men were placed in solitary confinement in a prison called “la 40,“ which was notorious for extreme torture, including electric shock and pulling off pris-oners' fingernails. Minerva and Maria Teresa, on the other hand, were released relatively unharmed on February 7. Once free, they continued their underground political work, albeit more discreetly. However, in May they were rearrested, taken to “la 40" and sentenced to 30 years. Again, the sisters were released. Their husbands Manuel and Leandro were transferred to a prison in Puerto Plata, a location much closer to their homes, which made visiting them frequently possible. Unbeknownst to them, this was all under orders of Trujillo.
With rumors rampant that an order for their death had been issued, the sisters traveled with an entourage that included children and elderly people, even though Minerva questioned whether the dictator would indeed dare to kill them. On November 25, 1960, Minerva, Maria Teresa, Patria (who had decided to accom-pany them out of solidarity), and their driver, a young anti-Trujilloist named Rufiño de la Cruz, set off by jeep to visit their husbands in Puerto Plata. Under orders from Trujillo, a group of six specially selected members of the secret military police ambushed the sisters and their driver and ordered them out of the car. They were taken to separate locations in a ravine so that the victims could not see each other's execution. All four were handcuffed, strangled, and clubbed to death. To make it seem as if it were an accident, the bodies were returned to the car and pushed down the ravine. The regime's cover story of an "accident backfired. No one believed the government's account. People all over the country were outraged that Trujillo would go so far as to kill women. Many believe that this incident was the beginning of the end of the Trujillo era, which culminated in his own assassi-nation six months later.
The Mirabal sisters' memory was commemorated for years in a very restrained manner, and the government treated the question of how and why they died guardedly. The main reason for this attitude was Joaquin Balaguer, the Dominican Republic's figurehead president during Trujillo's dictatorship, who remained in power until 1996. Julia Alvarez wrote a novel In the Time of Butterflies (1994), a fictionalized account of the lives of the Mirabal sisters that deals with this issue.
During their lives, the sisters were incarcerated several times and finally ambushed and brutally assassinated on November 25,1960, by the secret police. The murder of the Mirabal sisters outraged the majority of the population and is considered one of the events that helped propel the anti-Trujillo sentiment that led to his assassination six months later. A fourth sister, Bélgica Adela Mirabal Reyes, affectionately known as Dedé, is the sole survivor of the four siblings and the caretaker of the family's legacy.
Maria Teresa had carried on a clandestine romantic relationship with Leandro Guzman since the age of 14. They were married in 1958. The Mirabal sisters each had met and married men who not only became their husbands but also their partners in organizing the leadership activities of the anti-Trujillo movement.