Cowlitz casino developer David Barnett was in serious condition Tuesday afternoon after a Monday morning car crash.

Barnett, 49, was critically injured and unconscious after being thrown from the bed of a Toyota pickup at 6 a.m. Monday in Shoreline, police said.

No other vehicles were involved, the King County sheriff’s office said. The pickup’s female driver, 36, was uninjured.

The accident occurred five blocks from Barnett’s $1.3 million home on Puget Sound.

An emergency vehicle rushed Barnett to Harborview Medical Center in Seattle, said Sgt. John Urquhart of the sheriff’s office.

By Tuesday afternoon, his condition had improved from "critical" to "serious," according to a hospital spokeswoman, meaning Barnett’s life was not in immediate danger.

Detectives for the King County Sheriff’s Office were investigating the accident as a possible case of vehicular assault, Urquhart said.

That charge is used in cases of reckless driving or use of drugs or alcohol.

Urquhart described the pickup’s driver as Barnett’s "live-in roommate, whatever you want to call her."

He said a sample of her blood has been sent to a state lab and is likely to return in six to eight weeks.

Barnett, a Shoreline resident and real-estate developer, is the son of longtime Cowlitz Indian Tribe chairman John Barnett, who died last year.

In 2001, David Barnett bought 69 acres just west of La Center’s interstate junction.

The Longview-based tribe has since applied for that land to become their first reservation, the site of a proposed $510 million casino complex.

Until last year, Barnett owned 43 percent of the partnership that aimed to develop the casino and receive 24 percent of its net revenues.

Last November, Barnett sold an unknown share of that partnership to the California-based Paskenta Band of the Nomlaki Indians for an undisclosed sum.

Barnett is also a politically active residential developer in the Seattle area.

Tribal spokesman Phil Harju said Tuesday that he did not wish to speak for Barnett’s family and had no comment on the situation.