The crash happened near Calabasas, California, about 30 miles northwest of downtown Los Angeles on Sunday.
Los Angeles County Sheriff's Department confirms nine people were on board a helicopter. No victims survived. Authorities have not identified the victims, but ABC News sources confirm Bryant and his daughter, Gianna, were among those killed.
Orange Coast College head baseball coach John Altobelli also died in the crash, the college confirmed in a statement. Altobelli's brother, Tony, said the 56-year-old died along with his wife, Keri, and daughter, Alyssa, who was about 13 and played on the same basketball team as Gianna.
Federal Aviation Administration spokesman Allen Kenitzer said it was a Sikorsky S-76 and it was not known what caused the crash.
Los Angeles County Sheriff Alex Villanueva says his department's helicopters were grounded due to weather in the area on Sunday. Conditions were extremely foggy when Bryant's helicopter went down.
Bryant lived south of Los Angeles in coastal Orange County for much of his adult life, and he often used helicopters to save time and avoid Southern California's notorious traffic. Even as a player, he often traveled to practices and games by helicopter, and he kept up the practice after retirement as he attended to his business ventures.
Bryant got his start just outside of Philadelphia at Lower Merion High School.
He was drafted to the NBA out of Lower Merion in 1996 and spent his entire 20-year career with the Los Angeles Lakers, winning five NBA championships. He was awarded NBA MVP in 2008 and NBA Finals MVP in 2009 and 2010.
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"The Lower Merion School District community is deeply saddened to learn of the sudden passing of one our most illustrious alumni, Kobe Bryant," said the school district following news of Bryant's death.
Just last spring, Bryant was in West Philadelphia where he shared a powerful message to youngsters.
"That is the most powerful message within this book is that true strength comes from your vulnerability, you don't hide from being vulnerable that is your greatest source of strength and magic you have within you," he said. "Don't be afraid to dream."
The Sikorsky S-76 "is generally regarded as a good helicopter with a good safety record," said Gary C. Robb, an aviation attorney in Kansas City who wrote a textbook on helicopter crash litigation. "But parts fail, parts break. Anything can happen."
The crash occurred about 20 miles from Mamba Sports Academy, Bryant's basketball training complex in Thousand Oaks, California.
Bryant, who had four daughters with his wife, Vanessa, dedicated himself to boosting women's sports in his retirement, coaching and mentoring basketball players. Gianna, better known as Gigi, was a talented basketball player.
Colin Storm was in his living room in Calabasas when he heard "what sounded like a low-flying airplane or helicopter."
"It was very foggy so we couldn't see anything," he said. "But then we heard some sputtering, and then a boom."
A short time later the fog cleared a bit and Storm could see smoke rising from the hillside in front of his home.
Bryant retired in 2016 as the third-leading scorer in NBA history, finishing two decades with the Lakers as a prolific scorer with a sublime all-around game and a relentless competitive ethic. He held that spot in the league scoring ranks until Saturday night, when the Lakers' LeBron James passed him during a game in Philadelphia, Bryant's hometown.
"Continuing to move the game forward (at)KingJames," Bryant wrote in his last tweet. "Much respect my brother."
Continuing to move the game forward @KingJames. Much respect my brother 💪🏾 #33644— Kobe Bryant (@kobebryant) January 26, 2020
On Saturday night, James said he was "happy just to be in any conversation with Kobe Bean Bryant, one of the all-time greatest basketball player to ever play. One of the all-time greatest Lakers."
Before his retirement, Bryant made one last stop on Philadelphia where 76ers fans showed their respect for the NBA icon.
PHOTOS: Kobe Bryant honored during final Philly game
Bryant's retirement tour included a stop at the Wells Fargo Center and he even made a stop at his favorite cheesesteak shop, Larry's Steaks, the night before.
News of Bryant's death inspired an outpouring of grief around the sports world and beyond, but it was felt particularly painfully in Los Angeles, where Bryant was unquestionably the most popular athlete and one of the city's most beloved public figures. Bryant's popularity remained strong in his adopted hometown even during his sexual assault allegations.
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The Lakers' next game isn't until Tuesday night against the crosstown rival Clippers, but hundreds of fans - many in Bryant jerseys and Lakers gear - spontaneously gathered at Staples Center and in the surrounding LA Live entertainment complex on Sunday, weeping and staring at video boards with Bryant's image.
The NBA kept its games on as scheduled when the news broke, but the San Antonio Spurs and Toronto Raptors both took voluntary 24-second shot clock violations at the start of their game in honor of Bryant, who wore No. 24 for the second half of his career.
Bryant opened a production company and entered the entertainment field in retirement. He won an Academy Award in 2018 for his contributions to "Dear Basketball," an animated short about his relationship to the game. He also produced content for ESPN.
Bryant had one of the greatest careers in recent NBA history and became one of the game's most popular players as the face of the 16-time NBA champion Lakers franchise. He was the league MVP in 2008 and a two-time NBA scoring champion, and he earned 12 selections to the NBA's All-Defensive teams.
He teamed with Shaquille O'Neal in a combustible partnership to lead the Lakers to NBA titles in 2000, 2001 and 2002. He later teamed with Pau Gasol to win two more titles in 2009 and 2010.
A two-time Olympic gold medalist with the dominant U.S. team, Bryant retired in 2016 after scoring 60 points in his final NBA game. In December 2017, the Lakers hung banners retiring his No. 8 and No. 24 jerseys in the Staples Center rafters in an unprecedented double honor.
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The Kobe Bryant Gymnasium is a centerpiece of the campus at Lower Merion High School in Lower Merion, Pennsylvania. It was dedicated in 2010 and named after the school beloved alumnus.
Bryant looms large over the current generation of NBA players. After James passed Bryant on Saturday, he remembered listening to Bryant when the superstar came to speak at a childhood basketball camp.
"I remember one thing he said: If you want to be great at it, or want to be one of the greats, you've got to put the work in," James said.
James later teamed up with Bryant on the 2008 U.S. Olympic team in Beijing.
"He had zero flaws offensively," James said. "Zero. You backed off of him, he could shoot the 3. You body him up a little bit, he could go around you. He could shoot from mid-range. He could post. He could make free throws. ... He was just immortal offensively because of his skill set and his work ethic."
Bryant was a basketball superstar for his entire adult life. He entered the NBA draft straight out of high school in 1996 after a childhood spent partly in Italy, where his father, former NBA player Joe "Jellybean" Bryant, played professionally.
The Lakers acquired the 17-year-old Bryant in a trade shortly after Charlotte drafted him, and he immediately became one of the most exciting and intriguing players in the sport alongside O'Neal, who had signed with the Lakers as a free agent. Bryant won the Slam Dunk Contest as a rookie, and the Lakers gradually grew into a team that won three consecutive championships.
LeBron James and the Lakers found out about Kobe Bryant's death while on their team plane flying home from Philadelphia today after playing the Sixers last night @6abc #KobeForever #KobeRIP #KobeBryant pic.twitter.com/3XkWOGDSDj— Jeff Skversky 6abc (@JeffSkversky) January 27, 2020
Bryant and Gasol formed the nucleus of another championship team in 2008, reaching three straight NBA Finals and eventually winning two more titles.
Between those title runs, Bryant accomplished innumerable feats including an 81-point game against Toronto in January 2006. Bryant's final NBA seasons were dogged by injuries, but he still went into retirement with that jaw-dropping 60-point performance against Utah.
Investigators say the FAA is on scene and has secured a 5-mile flight restriction from area of the crash. NTSB crews are also investigating.
Sheriff Villanueva said during a Sunday night press conference that debris is scattered over an area the size of a football field. The county medical examiner, Dr. Jonathan Lucas, says recovery of remains may take several days. Lucas says investigators will try to make identifications of the victims as quickly as possible.
-- The Associated Press contributed to this report.