MIAMI-DADE COUNTY, Fla. – At least three people were killed Tuesday when two small planes collided with each other over the Florida Everglades, authorities said at an afternoon news conference.

Miami-Dade police identified the victims as Jorge Sanchez, 22, Ralph Knight, 72, and Nisha Sejwal, 19.

Authorities believe a fourth person may have been on one of the planes as the people onboard were believed to have been training and departed from Miami Executive Airport.

"The two planes were possibly training, which leads us to believe that you had a pilot and a trainer, or a trainer and a student, and another plane with a trainer and a student," Miami-Dade police Detective Alvaro Zabaleta said.

Miami-Dade Fire Rescue officials said one crash was reported shortly after 1 p.m. in an area several miles west of Miccosukee Resort & Gaming, near the border of the Everglades. Authorities arrived at the scene to find a second plane had crashed nearby.

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"Our crews were actually out here this morning, training for incidents just as this in the anticipation of aircraft accidents or incidents," Miami-Dade Fire Rescue Chief Andy Alvarez said.

Miami-Dade Fire Rescue personnel had to use an airboat to access the first crash site.

Daniel Miralles was fishing with some friends along a canal when he witnessed the mid-air collision.

"Right when I looked up is the minute they collided," Miralles said.

Miralles managed to record the aftermath as the two planes crashed to the ground.

Nisha Sejwal, 19, was killed in a mid-air collision over the Florida Everglades.

"It felt like there was an 18-wheeler behind me going 100 mph. That's what it sounded like," he said.

The Federal Aviation Administration said the planes involved in the crash were a Piper PA-34 and a Cessna 172.

A sign on the side of the aircrafts read "Dean International." Investigators have already been looking into the flight school after another small plane crash in May.

At that time, records showed there had been 23 incidents involving the school that required investigation within the past 10 years.

Two survivors from the May 3 crash were taken to Kendall Regional Medical Center, where they were treated for their injuries.

Tuesday's crash comes a year after Dean International student Mark Ukaere was killed when he took a small plane for a flight without permission. He was supposed to be flying with an instructor, but his girlfriend, Mercy Akinyemi, who lives in New Jersey, said he told her the instructor never showed up.

Robert Dean, the flight school's owner, attributed the cause of the crash that killed Ukaere, 29, to spatial disorientation due to the darkness of the night over the Everglades. Ukaere's body was found the morning after the crash near the wreckage.

It wasn't clear what caused Tuesday's mid-air collision.

Miami-Dade police said Southwest Eighth Street was closed in both directions from Krome Avenue to Naples because of the incident.

The National Transportation Safety Board is investigating the collision.