America remains in shock over the death of Kobe Bryant and his daughter Gianna in a helicopter crash on Sunday.

Investigators were working on Monday to determine the cause of the crash, which also killed seven others. Federal safety investigators are exploring factors including the pilot’s history and the chopper’s maintenance records. But much attention has focused on the foggy weather, which was considered dangerous enough that the Los Angeles police department and the county sheriff’s department had grounded their choppers.

It emerged on Monday that the helicopter received special clearance to fly in foggy conditions that had grounded police air operations. Officials said the pilot asked for air traffic controllers to provide “flight following” aid in his last radio message but was told the craft was too low.

About four minutes later, the pilot said he was climbing to avoid a cloud layer. When air traffic control followed up, there was no reply.

Bryant, 41, was one of the most famous athletes in America. When the retired basketball star’s death was confirmed on Sunday, television broadcasts were interrupted for breaking news bulletins.

Kobe Bryant obituary Read more

Among the other victims of the crash were a well-known California college baseball coach, John Altobelli, and his wife and daughter, Keri and Alyssa.

California authorities did not immediately confirm the identities of the victims but friends and family members said Gianna’s basketball coach, Christina Mauser, and Ara Zobayan, the aircraft’s pilot, also died. The other two victims were identified as Sarah Chester and her daughter Peyton, a team-mate of Gianna.

The medical examiner said it could take days to recover the remains of the victims due to the rugged terrain at the crash site.

Citing audio records between the pilot and air traffic control at Burbank airport, which are available online, the New York Times said the decision to give the helicopter special clearance would be at the centre of investigations.

“We’ll be looking at maintenance records of the helicopter,” the NTSB official Jennifer Homendy told reporters earlier. “We will be looking at records of the owner and operator of the helicopter and a number of other things.”

Kurt Deetz, who worked as a pilot for Bryant, told the Los Angeles Times the S-76B helicopter was considered safe, comparing it to “a Cadillac, a limousine – it’s limo-esque”.

Bryant won five NBA titles with the Los Angeles Lakers, one of the most famous sports teams in America. The team announced on Monday that its Tuesday game against the LA Clippers would be postponed.

Among those who paid tribute to Bryant following the crash were presidents past and present.

On Twitter, Donald Trump wrote: “Kobe Bryant, despite being one of the truly great basketball players of all time, was just getting started in life. He loved his family so much, and had such strong passion for the future. The loss of his beautiful daughter, Gianna, makes this moment even more devastating.”

Barack Obama also paid his respects.

“Kobe was a legend on the court and just getting started in what would have been just as meaningful a second act,” he wrote on Twitter. “To lose Gianna is even more heartbreaking to us as parents. Michelle and I send love and prayers to [Bryant’s wife] Vanessa and the entire Bryant family on an unthinkable day.”

Play Video 2:04 Kobe Bryant, his daughter Gianna, and their shared love of basketball – video report

Sunday’s Grammy awards were hosted at the Staples Center, the home of the Lakers and the stage for many of Bryant’s greatest achievements. Alicia Keys led a tribute at the start of the ceremony alongside Boyz II Men, who are from Bryant’s hometown of Philadelphia.

Keys said: “Here we are together on music’s biggest night celebrating the artists that do it best, but to be honest with you we are all feeling crazy sadness right now.

“Right now, Kobe and his daughter Gianna … are in our spirits, they’re in our hearts, they’re in prayers, they’re in this building. Take a moment and hold them inside of you and share our strength and our support with their families.”

Outside Staples Center, hundreds of mourning Lakers fans gathered throughout the day to leave flowers and share moments of silence, at times chanting “Thank you, Kobe!” and “MVP!” Makeshift memorials have popped up throughout the region, including outside a Shoe Palace mural of the star in LA, and near his family home in Newport Coast.

Michael Jordan, one of the few players in NBA history who has surpassed Bryant’s achievements, spoke of his own grief.

He said in a statement: “I loved Kobe – he was like a little brother to me. We used to talk often and I will miss those conversations very much. He was a fierce competitor, one of the greats of the game and a creative force.”

Tributes were also paid to Gianna, who was 13 and one of Bryant’s four daughters. The pair were travelling to Bryant’s basketball academy near Los Angeles, where Gianna was due to play in a tournament, when the helicopter crashed. She had spoken of following in her father’s footsteps and playing professionally in the WNBA.

The NBA commissioner, Adam Silver, said Bryant “was generous with the wisdom he acquired and saw it as his mission to share it with future generations of players, taking special delight in passing down his love of the game to Gianna”.

Play Video 2:03 Alicia Keys and Lizzo lead tributes to Kobe Bryant at Grammy awards – video

Bryant was also mourned outside the US. He spent much of his childhood in Italy where his father, Joe, played basketball professionally.

“All of the NBA players are important, because they’re legends, but he’s particularly important to us because he knew Italy so well, having lived in several cities here,” said the Italian basketball federation president, Giovanni Petrucci. “He had a lot of Italian qualities. He spoke Italian very well. He even knew the local slang.”

Bryant was hugely popular in China, where he was arguably more famous than Jordan and another Lakers star, LeBron James.

“From primary school to university, he accompanied the youth of countless people, and evoked the love for basketball among many young Chinese people,” the People’s Daily wrote in a post on social media platform Weibo.

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Bryant’s reputation was tarnished after he was arrested in 2003 over accusations he raped a woman at a Colorado hotel. Bryant denied the allegations, saying the encounter had been consensual.

The case was dropped after the alleged victim refused to testify at trial. Bryant later apologised to the woman, saying: “I recognise now that she did not and does not view this incident the same way I did.”

Bryant and the woman settled a separate civil suit out of court.