The helicopter had crashed into a hillside in Calabasas, California on Sunday morning, killing everyone on board.
"It's a logistical nightmare in a sense because the crash site itself is not easily accessible," Los Angeles County Sheriff Alex Villanueva was quoted as saying in a news conference by CNN.
He added that the investigation could be a "very extensive process."
Villanueva said the sheriff's office is working with the National Transportation Safety Board and the Federal Aviation Administration to check the cause of the crash and have already secured the site, the CNN report said.
The effort to recover the victims' bodies has also begun but could take a couple of days, Los Angeles County Chief Medical Examiner Jonathan Lucas said, "given the terrain and the condition of the site."
"We're doing everything we can to confirm identifications and give closure to the families involved."
Bryant, an 18-time NBA All-Star basketball legend, died in the crash in Calabasas, plunging the sporting world into gloom. He was 41.
Bryant's daughter Gianna, 13, was also confirmed dead. They were among nine people on board who were all killed in the crash. The group was travelling for Gianna's basketball game which was to begin at noon, local time, in the Thousand Oaks area. The S-76 helicopter crashed just before 10 a.m. in a steep hilly area about 30 miles northwest of Los Angeles.
( With inputs from IANS )