BEND, Ore. -

Oregon State Police asked Wednesday to hear from any other witnesses to a fatal motorcycle-car collision last Thursday evening on Highway 97 near Lava Butte, about six miles south of Bend.

A Portland woman riding as passenger on a motorcycle was killed and two men were hospitalized at St. Charles Bend with non-life-threatening injuries.

Details about the about the manner and cause of the crash are being withheld as the investigation continues, troopers said.

Troopers asked that anyone who has not spoken to the lead investigator, Trooper Justin Lane, contact him at (541) 388-6213, extension 5128.

Around 5:40 p.m. on Thursday, May 22, a 2013 Harley Davidson motorcycle with two riders and a 1998 Ford Mustang with one occupant were heading north on Highway 97 near milepost 149 north of Sunriver when the two vehicles collided, troopers said.

The motorcycle then crashed into the center concrete barrier before coming to rest on the highway several hundred feet from the estimated point of impact, OSP said. The Mustang came to rest on its top off the side of the highway.

The motorcycle passenger, identified as Lisa Michelle Tomlin Grall, 53, of southeast Portland, was pronounced dead at the scene.

The male motorcycle operator, Phillip Martin Branum, 62, of La Pine, was flown by AirLink helicopter to St. Charles Bend with what troopers called serious but non-life-threatening injuries.

Both riders were wearing helmets, they added.

The car's driver, Cory L. McBride, 27, of Tucson, Arizona, was seriously injured and taken by ambulance to the Bend hospital with reported non-life-threatening injuries, troopers said.

OSP troopers and a collision reconstructionist from Bend and La Pine offices are leading the investigation. OSP was assisted at the scene by the Deschutes County Sheriff's Office, Bend Fire Department and ODOT.

OSP and ODOT said the fatal crash served as a tragic reminder to all drivers and motorcycle operators that May is "Motorcycle Safety Awareness Month" in Oregon.

According to ODOT, 43 people lost their lives in motorcycle crashes in 2013, down from 51 in 2012. Last year, 73 percent of fatal motorcycle crashes in Oregon were attributed to the motorcyclist committing the primary error leading to the crash.