Spina said there was no way to express the “remorse and contrition” felt by Taylor and his family, Spina said.
“We trust that in time there can be healing for parties directly affected by this terrible tragedy,” said Spina.
Taylor is charged with manslaughter in the wreck, which happened May 25 in Auburn. Authorities allege Taylor was driving about 90 mph and had traces of the psychoactive part of marijuana in his system when he rear-ended an SUV carrying the couple.
Rod Bramblett, 52, was driving and died of a head injury. Paula Bramblett, 53, died of multiple internal injuries.
There was no indication the teen tried to stop before the wreck, authorities said.
Spina said Johnston had spent the day at Lake Martin with his girlfriend’s family and “had been without sleep for a period of time.”
“He did not drink at the lake and he did not partake of marijuana while at the lake. This is undisputed,” Spina said.
Experts say that marijuana can stay in someone’s system for as long as 30 days or more, Spina said, and the teen has consistently told authorities he fell asleep while driving.
Authorities previously said there wasn’t any indication that alcohol or cellphone use played a role in the wreck, in which Johnston was not seriously injured.