An Iowa family of four was found dead in the condominium where they stayed while on vacation in Tulum, Mexico, police confirmed Friday.

Kevin Wayne Sharp, 41, his wife Amy Marie Sharp, 38, and their children Sterling Wayne Sharp, 12, and Adrianna Marie Sharp, 7, were reported missing early Friday to police in Creston, Iowa, by their immediate family members. The Sharps had planned to return home Wednesday, family members said.

Police quickly made contact with the U.S. State Department, Creston police said in a statement. A welfare check at the condominium where the family was believed to be staying led to the discovery of the four bodies.

Autopsies are being performed in Mexico. It is not immediately clear what led to the Sharp family’s deaths, but Creston police chief Paul Ver Meer told KCCI that there were no signs of traumatic injury.

Local Mexican authorities have taken over the investigation, according to the State Department. The Mexican Tourism Board said in a statement obtained by CBS that “preliminary reports from local officials conclude that there were no signs of violence or struggle.”

The Sharps left the United States for Cancun, Mexico, on March 15, according to a Facebook post. The family then rented a car and drove to Tulum, where they were renting a condo, according to Amy Sharp’s sister Renee Hoyt, who spoke with the Creston News Advertiser. The Sharps were supposed to return to the United States about 2:45 p.m. Wednesday from Cancun and arrive in St. Louis about 6 p.m.

The Sharps had informed their family members on March 15 that they had arrived safely at their condominium in Tulum. So when family members didn’t hear from them Thursday – after they were supposed to have arrived in St. Louis – they became worried.

The family’s mysterious deaths come amid increased travel warnings to Quintana Roo state, which is home to Tulum – a popular destination for those looking to explore Mayan ruins or snorkel in limestone sinkholes. The State Department issued a level 2 advisory to those traveling to Quintana Roo on March 16, meaning visitors should be cautious because of increased crime there. Department officials cited a spike in Quintana Roo’s homicide rate since 2016.