A day of sailing lessons turned into a tragedy on the water when a boating accident claimed the lives of two young children and injured four others and now questions remain into what led up to the heartbreaking tragedy.

Investigators with the Florida Fish and Wildlife Conservation Commission were seen going in and out of the Miami Yacht Club on Watson Island for hours after the tragic incident on Monday.

Officials said a barge and a sailboat crashed off the coast of Hibiscus Island during a youth sailing session as part of the Miami Youth Sailing Foundation’s summer program.

The Yacht Club offers both adult and youth sailing lessons.

Among those who arrived Monday for their lesson was 9-year-old Enzo Piffard. He had just arrived on shore for his last week of summer camp when the crash occurred.

“I was on the shore, had just gotten there,” he said.

He said he’s sailed with the Yacht Club several times and is even on the racing team.

“I saw like everything happen and they all went flying off the boat. The second it happened, they called all of us to shore. Two of them were found really quickly while three of them there was helicopters, boats,” said Piffard.

After a search and rescue effort by multiple agencies, six people were pulled from the water. Four were rushed to Jackson Memorial Hospital in critical condition, while two others, a 19-year-old camp counselor and a 12-year-old girl, are said to be OK.

Upon arrival to the hospital, two children, a 7 and 13 year old, were dead on arrival. The other two young victims, an 8 and 11 year old girl remain critical as of late Monday night.

The Miami Yacht Club confirmed Monday that all those on the sailboat were part of the Miami Youth Sailing Foundation.

According to the foundation’s website, the program requires all participants to bring U.S. Coast Guard approved Type III life jackets. Witnesses told 7News the children appeared to be wearing them at the time of the incident.

In a written statement, the Miami Yacht Club said:

“At this time, details are still emerging and we are actively gathering all available facts. Our priority is the safety and well-being of everyone involved and we are working closely with the appropriate authorities and organizations to understand the situation fully.”

Parents were left shaken as they picked up their children from the camp on Monday. One of them told 7News they had faith in the program but acknowledged the emotional toll of the crash.

“I’m confident in them. This is an accident,” said a parent.

An investigation is now underway as the community is left searching for answers.

The sailboat remains submerged under the barge as of late Monday night.

It also remains unclear if the yacht club will re-open on Tuesday.