An autopsy report says the girl suffered deep cuts to her back and left leg. She was rushed to the hospital following the accident, but died in surgery.
Squirrell had been taking part in a training exercise off Huntington Beach at the time of the accident.
Crow, a 32-year veteran with the Marine Safety Division, said he never saw Squirrell in the choppy waters. Orange County prosecutors determined there was no evidence of a crime and that it was simply a tragic accident.
In the days following the accident, Squirrell's family received an outpour of support from the community, something for which they expressed gratitude, as they asked the public to pray for Crow.
An emotional memorial followed in the water off Huntington Beach, where family and friends tossed flowers into the ocean. Squirrell was finally laid to rest after a funeral service at Saddleback Church's Irvine campus.
It was the first death in the 45-year history of the junior lifeguard program, which was suspended for two days after the accident. The program teaches more than 1,000 junior lifeguards each year.