NORTHAMPTON - The Registry of Motor Vehicles has revoked the license of Matthew Kostanski, the driver of a vehicle involved in a two-car crash that killed Emily N. Weston in Sunderland Sunday.

Meanwhile, a passenger in Weston's car, 53-year-old Carey Collins of Indianapolis, was discharged from Baystate Medical Center in Springfield Wednesday evening, according to a hospital spokesman.

Authorities still have yet to say what they believe caused the fatal crash, but state police detectives assigned to the district attorney's office appealed to the Registry of Motor Vehicles Monday to revoke Kostanski's license.

"If ... the Registrar determines that a person's operation of a motor vehicle poses an immediate threat to public safety, the Registrar can revoke that person's license immediately for an indefinite period," according to a statement from the district attorney's office.

Mary Carey, spokeswoman for the Northwestern district attorney's office, said she expects by the end of the week to release a statement with more information on the probe into the cause of the crash.

Weston, 18, of North Hatfield, graduated in June from the Pioneer Valley Performing Arts Charter Public School in South Hadley. She was pronounced dead at Cooley Dickinson Hospital in Northampton shortly after the crash.

Calling hours for Weston are Friday from 3 to 7 p.m. at the Ahearn Funeral Home, 783 Bridge Road, Northampton. Her funeral will be Saturday at 1 p.m. at the Helen Hills Hills Chapel on Elm Street in Northampton, with a gathering to follow at the Lions Club Pavilion in Hatfield.

Police have said Kostanski, 23, of Greenfield, was driving south on Route 116 near Bub's Bar-B-Q about 6 p.m. Sunday when his vehicle drifted into the wrong lane, striking Weston's car. Weston tried to veer out of the way, police said.

Kostanski was treated at Baystate Franklin Medical Center in Greenfield and released a short time later. A dog inside his car was not hurt, police said.

Meanwhile, students at PVPA are coping with the tragedy with support from the school.

"I expect that many students will have delayed reactions to this horrible news over the next few days and weeks," Scott Goldman, head of school, said in a letter sent to parents. "Please know that we will support them, and you, in getting through this experience as a community.

In the letter, Goldman also said the entire school gathered at lunchtime Monday with a small group of teachers and students performing a song in honor of Weston, followed by silence and reflection.

"The PVPA staff was incredible today with your children," Goldman wrote. "In spite of their own personal heartbreak, they took care of your children in a heroic fashion."

James F. Lowe can be reached at jlowe@gazettenet.com.