A California couple visiting Mexico for the holidays was shot and killed on Wednesday when armed gunmen fired on their vehicle, according to authorities.

Rafael and Gloria Cardona were visiting family in Angamacutiro, Michoacan state at the time of the attack, a US official told CNN. The woman died at the scene and the man died shortly after in the hospital.

Their three children, two of whom are minors, were not present during the shooting and are currently with extended family in Angamacutiro, the US official said. The US State Department is in contact with their adult daughter.

Rafael Cardona’s brother-in-law is Hermes Arnulfo Pacheco Bribiesca, a Mexican government official in Amangcutiro who assumed office after the kidnapping and murder of his predecessor in late October, according to the US official.

According to a statement Rafael Cardona’s brother, Cesar, gave to local police, the couple were driving Hermes’ van when they were killed, the US official said.

The motive for the attack has not been confirmed by Mexican authorities.

The couple had arrived in the Pacific coast state on November 30, local authorities said earlier.

In a statement sent to CNN, a US State Department spokesperson confirmed the death of both US citizens and offered their “sincerest condolences to their families for their loss.”

“We are closely monitoring local authorities’ investigation into the reported killings,” the spokesperson said.

A mass will be held in Angamacutiro Saturday to commemorate the couple, local authorities said. The municipality has canceled all celebrations for the rest of the month, authorities added.

Michoacan has been long affected by gang violence, with cartels moving into the state in the 1980s. Its homicide rate today is more than twice the country’s average. Nationally, Mexico’s homicide rate is among the highest in the world.

The state is also Mexico’s largest grower of avocados – a market long troubled by violent groups and corrupt public authorities, researchers at the Global Initiative Against Transnational Organized Crime said in a report this year. Nearly three-quarters of Mexican avocados come from Michoacán.

Gangs such as the Zetas and Familia Michoacana were formed in the state, which has become home to drug production and drug traffickers who target local farmers to cultivate marijuana and other drugs, according to a report from Insight Crime.

More than 100,000 people remain missing in the country, with no explanation of their fate. According to think tank Mexico Evalua, around 95% of all crimes nationwide went unsolved in the country in 2022. (CNN, excluding headline)