PORTLAND, Ore. (KOIN) -- A 19-year-old motorcyclist remains hospitalized in critical condition after a hit-and-run crash last Friday that tossed her cell phone into the other driver's car and led to his arrest.

The crash, which happened at SW Farmington Road and 157th Place in West Beaverton, happened when Sarahy Rodriguez was on her way home from her grandmother's house around 7:30 p.m. Witnesses, who stayed with the injured teen, told police a dark-colored Scion XB just kept going after the collision.

Her helmet likely kept her alive, investigators said. The break in the case came when her sister, Cindy, noticed her cell phone was pinging about a mile away -- near Southwest 170th Avenue and Vincent Street -- and went to that spot. Cindy spotted a Scion XB with damage from a crash.

"I'm glad we found the phone, I'm glad we found the person," Cindy told KOIN 6 News. "But it's sad."

Deputies arrested Julian Borjas-Diaz after they said they determined the 27-year-old was driving the Scion at the time of the crash. He was booked into the Washington County Jail on a felony hit-and-run charge.

Sarahy's mother, Trini Miranda, said once she saw her daughter she "started screaming and crying. I could not believe that it was my child that I was seeing."

But she is so thankful the bystanders stayed with her daughter until help arrived.

"There's not enough words to thank them," she said.

Sarahy Rodriguez has a long road to recovery, but her mother hopes that, even in the chaos of a crash like this, people won't forget their compassion or their care.

"The human thing to do," Miranda said, "is to stop. Stop and make sure that person is OK."

Anyone with information about the crash is asked to contact the sheriff's office about the ongoing investigation.