PUEBLO, Colo. -- Police in Pueblo are trying to determine how two young sisters and their babysitter all drowned on Monday.
It happened at the Pueblo Grande Village mobile home park around 2 p.m.
Police said responding officers found 3-year-old Azucena Gandarilla, 6-year-old Amaya Gandarilla and 17-year-old Joo Lee unresponsive, according to the Denver Post.
Officers and others tried to revive the victims, but despite their efforts, the three were later pronounced dead by the coroner’s office.
Matt Lane, CEO and Founder of Safe Splash Swim School , said drownings can happen in the matter of seconds and in just inches of water.
"Strange things happen, but I can tell you kids can drown in literally inches of water. It's not about the depth, it's not about the volume. It's just about if hey have their airway underwater for a matter of time."
There is no foul play suspected, Capt. Joe Garcia of the Pueblo Police Department told the Pueblo Chieftain .
“I think it’s just a horrible tragedy,” Garcia said.
The pool ranges from two to eight feet deep, and there are signs warning people to swim at their own risk, according to KVOR radio .
"I don't believe that swimming in a pool absent of a lifeguard is any less risky or dangerous than swimming in a pool with a lifeguard," Lane said of the unmanned pool, as long as swimmers are equipped to survive a dangerous situation.
Lane said any children who are brought into a swimming pool should be trained at a school like Safe Splash, so they can survive risky situations that any swimmer can encounter.
Pueblo police Sgt. Eric Gonzales told KKTV it's not clear if the victims lived at Pueblo Grande Village or were just visiting.
Lane said he isn't quite sure how the children drowned in the presence of an older teen, he said a situation having nothing to do with the water could lead to a drowning.
An investigation is underway, and police say they expect to release additional details when more is known.