A Mexican musician, his pregnant wife, their 3-year-old daughter and a young woman who worked for the family were killed inside their home in a shocking attack that has drawn widespread attention across Mexico.

The victims were found late Tuesday, Sept. 1, inside a residential complex in the upscale Zona Esmeralda area of Atizapán de Zaragoza, in the State of Mexico, according to authorities. A 6-year-old boy was also inside the home and was found alive and unharmed.

The musician was identified by multiple reports as Jonathan Meléndez, 38, a keyboardist, composer and founding member of the Mexican indie-rock band Camilo Séptimo. His wife, Ana Paula Barragán, 35, was pregnant at the time of her death. Their 3-year-old daughter, Sofía, was also among the victims.

The fourth victim was identified as Aleida Romero Victorio, a 21-year-old woman who worked as a nanny or domestic worker for the family. The family dog was also found dead at the residence.

Authorities said the incident occurred sometime between approximately 5:30 p.m. and 7:40 p.m. on Sept. 1. Neighbors reportedly alerted authorities after hearing disturbances, and police later discovered the victims inside the apartment.

The investigation quickly led to two arrests. Authorities identified the suspects as Diego Sebastián “N” and Gerardo “N.” Investigators believe one of the suspects had a business relationship with Meléndez and may have used that relationship to gain access to the residence.

A motive has not been definitively established. Authorities have said the investigation is continuing, while reports indicate that robbery does not appear to explain the attack because nothing was apparently taken from the home.

The tragedy has also shaken Mexico’s music community. Camilo Séptimo paid tribute to Meléndez, remembering the musician with affection and gratitude for his contribution to the band’s history and music.

Ana Paula had largely stayed away from the public spotlight despite her husband’s career. Reports describe her as a private person who shared relatively little of her personal life online. She and Meléndez had been together for years and were raising their young daughter while expecting another child.

The investigation remains ongoing as authorities work to establish exactly what happened inside the residence and the full circumstances surrounding the deaths.