ANAHUAC, Texas – A twin-engine Boeing 767 crashed into Trinity Bay near Anahuac early Saturday afternoon, and authorities said they believe all three people on board are dead after human remains were found.

The plane was on its way to George Bush Intercontinental Airport from Miami, Florida, when it crashed, the Federal Aviation Administration said.

According to the Texas Department of Public Safety, a civilian called the Chambers County Sheriff's Office around 12:40 p.m. Saturday to report seeing a plane go down in the water.

The FAA said initial reports indicated the plane was Atlas Air Flight 3591.

READ: What we know about the plane

According to Atlas Air Inc.'s website, the company transports items from "precious perishables or heavy construction equipment to arranging passenger charters for celebrities or dignitaries."

VIDEO: Sky2 over Trinity Bay

The crash happened in an area known as Jack's Pocket in northern Trinity Bay, according to authorities.

Sky2 aerials showed a trail of debris in the water up to 1 mile long. Authorities said they saw everything from bedsheets to women's clothing to cardboard boxes to a lot of fiberglass among the debris.

"Who knows what's under the water that we can't see, but it looks like total devastation from the aircraft part," Chambers County Sheriff Brian C. Hawthorne said. "Knowing what I saw, I don't believe anybody could survive it,"

The FAA said initial reports indicated that there were three people on board.

PHOTOS: Boeing 767 cargo jetliner crash

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The sheriff said witnesses told authorities the plane went into a nose dive, then went into the water nose-first.

Hawthorne said witnesses said they heard what sounded like lightning before the plane went down.

"We first started getting 911 reports of eyewitnesses that watched it go nose-first into the bay," Hawthorne said.

According to DPS, the aircraft broke up on impact in approximately 2 to 4 feet of water. Dive teams are searching for the black box.

"The problem that we're gonna have, that everybody is gonna have in this recovery process, is that the water is goes from about five feet deep to zero. And that zero feet deep is nothing by mud marsh," Hawthorne said. "(That area) is best known for its duck hunting, so it's not gonna be an easy recovery task for us to do."

VIDEO: Sheriff provides update after cargo jet crash

Investigators could be at the scene for weeks, the sheriff said.

"We haven't been able to find any survivors or any remains," Hawthorne said. "I would say that the largest chunk of the plane that I could actually visually put my eyes on is probably not much larger than about 50 feet."

Below is a picture of the plane's flight path into Houston from Miami before the deadly crash.

You can see where the plane potentially had trouble and deviated from the remainder of its flight path to IAH (denoted by the dotted blue line.)

The FAA confirmed they lost contact with an aircraft, but specific details were not released.

The Flightaware web site showed an image of Atlas Air Flight 3591 as an Amazon Prime Air cargo jet. It has been confirmed by Amazon that the cargo plane belonged to the company.

Hawthorne said the airspace above Chambers County is a popular flight path for planes traveling from the East Coast to Bush Airport.

Multiple agencies are at the scene in Trinity Bay, including:

U.S. Coast Guard

Houston Police Department

Chambers County Sheriff's Office and Fire Department

Harris County Sheriff's Office

Texas Parks and Wildlife

Texas Department of Public Safety

Baytown Dive Team

The sheriff said three civilian airboats helped authorities with the search.

"You know we're Hurricane Harvey survivors so when they called me and told me we had a major aircraft crash in the bay, I made some phone calls and people who helped us in Harvey were out there helping us, you know trying because we obviously we were hoping there would be survivors," Hawthorne said.

WATCH: NTSB discusses deadly cargo jet crash in Chambers County

The FAA and the National Transportation Safety Board will investigate. Atlas Air said it is cooperating with both agencies.

KPRC crew was the only crew on water where the jet Boeing 767 landed in Trinity Bay. Packages, items of clothing, parts of the plane along with an air vest were among the debris found scattered along where the jet plane crashed.

What does a 767 cargo jet look like?

It is a midsize to large jet airliner with a seating capacity for 181 to 375 people.

Here's what we know about the plane so far.

Below are statements KPRC2 has received about the plane crash.

The FAA released the following statement:

"A twin-engine Boeing 767 cargo jetliner operated by Atlas Air Inc. crashed into Trinity Bay near Anahuac, Texas, shortly before 12:45 p.m. (Saturday).

"The Federal Aviation Administration issued an Alert Notice (ALNOT) on Atlas Air Flight 3591 after losing radar and radio contact with the Boeing 767 approximately 30 miles southeast of Houston George Bush Intercontinental Airport. The aircraft was flying from Miami to Houston.

"Initial reports indicate three people were aboard the aircraft.

"Please contact local search and rescue officials for further information about the emergency response.

"FAA investigators are on their way to the accident site and the National Transportation Safety Board has been notified. The NTSB will be in charge of the investigation.

"The FAA and NTSB do not release names of people aboard aircraft. We defer to local officials to do that at the appropriate time."

Atlas Air Inc. released the following statement:

"This is to confirm that an Atlas Air 767 cargo aircraft Flight No. 3591 operating from Miami to Houston has been involved in an accident this afternoon. We understand the aircraft went down near the city of Anahuac Texas, in the Trinity Bay. We can confirm there were three people on board the aircraft. Those people and their family members are our top priority at this time. Atlas Air is cooperating fully with the FAA and NTSB. We will update as additional information becomes available."

Dave Clark, senior vice president of worldwide operations at Amazon, released the following statement:

"Our thoughts and prayers are with the flight crew, their families and friends along with the entire team at Atlas Air during this terrible tragedy. We appreciate the first responders who worked urgently to provide support."

Bill Flynn, Atlas Air chief executive officer released the following statement:

“Our thoughts and prayers are with all those who have been affected. This is a sad time for all of us. Our team continues to work closely with the NTSB, the FAA and local authorities on the ground in Houston. We would like to commend the efforts of all of the first responders. We sincerely appreciate their efforts and support in the investigation.”