The driver, a 47-year-old Kailua-Kona man, was booked Sunday on two counts each of third-degree promotion of a dangerous drug, third-degree promotion of a detrimental drug and possession of drug paraphernalia. In addition, the man was also booked on suspicion of driving under the influence of an intoxicant and two counts of causing negligent injury.

The man and boy are at The Queen’s Medical Center. Emil Spencer, 40, remained in critical condition today, according to hospital officials. Queen’s declined to release information on 7-year-old Kihei Spencer, but Kona police Capt. John Dawrs said the boy is critical but showed signs of improvement yesterday.

The two were injured as they walked on Ali'i Drive.

Brian Pajimola of Hualalai, who witnessed the accident, said he was driving south on Ali'i Drive at about 12:40 p.m. Sunday when a large pickup truck approached from the other direction and crossed the center line, prompting Pajimola to drive off the side of the road to avoid it.

The truck then swerved back into the northbound lane at 45 mph or more, Pajimola said. As the truck passed, the driver appeared to be leaning over inside the truck as if he were reaching for something.

Pajimola had just passed the Spencers as they were walking south on the mauka side of the highway. He said the father and son appeared to be returning from an outing at Magic Sands Beach. Both were in swim trunks and the boy had no shirt on.

Although they were facing the truck, they had few options, Pajimola said, since there was a rock wall along the shoulder of the highway and nowhere to flee except into the middle of the road.

Police said the Spencers were struck by a 2003 Ford pickup truck near the intersection with La'aloa Avenue. Pajimola said he saw the driver try to hide a black leather fanny pack in some bushes by the side of the road, and he later pointed the bag out to police.

Police recovered the truck and the fanny pack, and planned to obtain search warrants to collect more evidence.