"Autopsies are being performed in Mexico and results are pending," the Creston Police Department said in a statement.
There were no signs of foul play, according to police, KCCI reported. A local news outlet in Mexico reports investigators are looking into whether food poisoning or a gas leak could have been responsible.
The family had not been heard from since they left for Mexico on a trip on March 15. KCCI reports that according to family members' social media posts, Kevin, 41, Amy, 38, Sterling, 12, and Adrianna Sharp, 7, were expected to arrive in St. Louis on Wednesday to attend a basketball game in Danville, Illinois.
Relatives had filed a missing persons report through the U.S. Embassy in Mexico.
Terrible update, the Sharp family was found dead in their condo in Tulum, Mexico. Dad, mom, son and daughter. Police are working with state department and Mexican authorities to figure out what happened.
— Hannah Hilyard WISN (@Hannah_WISN) March 23, 2018