Police have determined that both the middle schooler on a bike and the driver of a school bus she collided with contributed to her death in a Rockville crosswalk in October.

In a news release Friday, Montgomery County Police said a collision reconstruction team found that 11-year-old Summer Lim “was at fault in the collision for entering the crosswalk while the bus was already occupying the intersection.”

The report also determined that 55-year-old Ivan Rivas, who has worked for the Montgomery County Public Schools since 2001 and had driven the route for more than 15 years, “was negligent for moving the bus forward after initially coming to a stop.”

Detectives found that after the initial impact Rivas drove 27 feet further. He was cited with one count of negligent driving, contributing to a fatal accident.

The Montgomery County State’s Attorney’s Office also reviewed the Oct. 9 incident.

Summer, who attended Earle B. Wood Middle school, was riding her bicycle eastbound on the sidewalk along Bauer Drive prior to the crash. She attempted to cross Russett Road and entered the crosswalk at about 3:15 p.m., less than half a mile from the school.

Despite life-saving efforts, emergency workers pronounced Summer dead at the scene.

Asked whether Rivas still works for the school district, a spokeswoman replied in an email on Friday: “Any further actions regarding the staff involved will be handled as a confidential personnel matter.

“Our deepest sympathies remain with the family and loved ones of the student, and we recognize the profound impact this loss has had on the school community,” the statement continued, adding that the schools will continue to provide counseling to students and staff.

It was not immediately clear on Friday whether Rivas had retained an attorney.