Andromahi “Mahi” Trivellas ’11 sustained critical head and spinal injuries when she was struck by a car in a hit-and-run accident on the corner of York and Elm streets at 1:05 a.m. Sunday, police and witnesses said.

The Branford freshman and Yale women’s lacrosse player from Chadds Ford, Pa., was still in critical condition as of Sunday evening, according to a Yale-New Haven Hospital spokesperson.

Hospital administrators did not release any further details about her condition.

Police said they are still looking for the driver of the car, which they described as a blue Crown Victoria last seen heading east on Elm Street. Police officials declined to comment on whether alcohol or speeding were factors in the collision.

“The driver responsible for the incident fled the scene,” city spokeswoman Jessica Mayorga said in a Sunday statement.

The accident came only four days after a Yale graduate student was hit by a car at the same intersection and suffered non-life threatening injuries.

Three eyewitnesses who were in a car at the intersection of York and Elm streets at the time of the accident — all of whom asked to remain anonymous — said the car was moving at full speed when it hit the student. The car drove away immediately after the accident, they said.

Police cars, ambulances and fire trucks initially blocked access on Elm Street between York and High streets, where a pool of blood and a gold-colored shoe were left on the road.

Police officers at the scene of the incident declined to comment on details of Trivellas’ injuries.

Police responded quickly after the accident, the eyewitnesses said, because they were behind the car at the intersection when they accident took place. There were both New Haven and Yale police officers at the scene.

Barrett Williams ’10 said he was walking back to his suite in Trumbull when he saw Trivellas “crumpled over” on Elm Street with her chest and head folded over her knees. He said she did not seem to be moving.

Williams is a staff reporter for the News.

Marcus Oda ’09 said he saw Trivellas lying on the road shortly before she was carried into an ambulance. He said she was conscious and moving.

“She was mostly screaming in pain,” he said. “I couldn’t understand what she was saying.”

Claire Elaisberg ’10, one of Trivellas’ lacrosse teammates, said members of the women’s lacrosse team visited Trivellas on Sunday and have been in e-mail correspondence with Trivellas’ parents, who were with their daughter at the hospital.

Elaisberg, who visited Trivellas on Sunday evening but did not see her in person, said Trivellas was sedated.

Andromahi has a twin sister, Myra Trivella ’11, who is in Saybrook College.

Branford Master Steven Smith could not be reached for comment Sunday.

In the earlier accident this week, a graduate student pedestrian was hit by a car, but suffered only minor injuries.

Tyce Walters ’09, who witnessed Wednesday’s accident, said the female victim stood up after being struck in the accident, though her chin was cut and bleeding.

Mayorga requested that anyone with information about Trivellas’ Sunday accident call the NHPD immediately.