SAN JUAN, Puerto Rico (AP) — Authorities in the U.S. Virgin Islands on Tuesday investigated what caused a helicopter crash that killed at least four people.

The crash occurred Monday at the western end of St. Thomas around Botany Bay, said Erik Ackerson, emergency management spokesman. He said officials were not yet releasing the names of those killed.

The Virgin Islands Daily News reported that the Antilles School announced it canceled classes Tuesday because it was believed that a senior student and his family were aboard the helicopter.

School spokeswoman Ananta Pancham declined to comment. The school said in a Facebook post that it would issue an official statement about “the tragedy that has impacted our School community when official details have been released and next of kin notified.”

Meanwhile, country singer Kenny Chesney identified one of the victims as pilot Maria Rodriguez in a tribute he posted on Instagram, calling her “a dear friend to me and to our island community.” He added that he had flown with her for more than 15 years.

According to Aviation International News, Rodriguez owned two helicopter companies, flew the Obamas in 2017 and was praised for her mission work following hurricanes Irma and Maria. In 2018, she was recognized as “Pilot of the Year” by Helicopter Association International.