Lucas Anthony Tang suffered head injuries Sunday when he landed on rows of seats minutes after the Los Angeles Lakers beat the Golden State Warriors 117-89, police said. The boy later died at a hospital.
"Somehow the child went over the edge of the section," Officer Julie Sohn said.
Police were releasing few details about the incident as they tried to determine what happened.
Sohn said the boy's family was taking photographs at the time of the fall.
The Los Angeles Times, citing unidentified police sources, said the toddler's family was looking at digital photographs and lost track of him. He somehow got over the top of the glass barrier, the newspaper reported.
Sohn, however, said she could not confirm those details.
The luxury boxes have tiers of seats, fronted by concrete walls. Atop the walls are glass barriers. The barrier varies in height but at its lowest point is about the height of an adult's waist, said Michael Roth, a spokesman for Staples and owner, AEG.
Roth declined to be more specific about the height and it was not immediately clear from which point the boy fell. He said the toddler fell into a general seating area about 30 rows up from the court.
The child fell 25 to 50 feet, according to various estimates from police detectives, fire officials and Roth.
Witnesses said the boy was moving his arms, legs and head when paramedics put him in an ambulance, Roth said.
The luxury box met all building requirements, Roth said. The 950,000-square-foot stadium opened in 1999 and has 160 luxury suites on three levels. "In 11 years, we've never had an incident like this," he said.
A message seeking comment from the city Department of Building and Safety was not immediately returned on Monday.
The police department's juvenile division, which has investigative responsibility when a victim is under age 11, was handling the probe. "It's procedural" and did not necessarily indicate that a crime was involved, Sohn said.
The arena was conducting its own investigation, Roth said.
Roth declined to release details about the boy's family but said the luxury box as with most suites probably was owned by a corporation.
"Our condolences and prayers go to the Tang family," Roth said a short prepared statement.
The Lakers organization issued a statement expressing shock and sadness at the tragedy.
"To go from a moment of happiness and enjoyment, to the loss of this boy's life, is tragic and heartbreaking. We would like to ask Lakers fans to join us in keeping Lucas and his family in our thoughts and prayers," the statement said.
Roth said Monday night's game between the Los Angeles Clippers and New Orleans Hornets would go on as scheduled.
The arena is home to the NBA's Lakers and Clippers, the NHL's Los Angeles Kings and the WNBA's Los Angeles Sparks.
Adjacent to the popular LA Live entertainment complex, Staples is also one of the city's major venues for concerts and special events such as the Grammy Awards.