School officials said classes would begin as planned Tuesday in the district, which serves Newtown and surrounding communities. Despite the Labor Day holiday, Council Rock South will be open from 1 to 4 p.m. Monday to offer grief counseling to students and parents.
"We ask for your thoughts and prayers for our students and their families," Klein said in the statement.
State police in Honesdale received a call Saturday at 11:34 a.m. about a rollover accident on Goosepond Road, near Wallenpaupack Lake Estates, in Wayne County's Paupack Township, authorities said. The area is about 70 miles north of Philadelphia.
"Upon arrival, troopers found a 2001 Chevrolet Suburban with six juvenile occupants," a state police spokeswoman said in a written statement.
Dead at the scene was Keffer, who was listed as 15 on a lacrosse recruiting website and whose hometown could not be confirmed. Digney, of Holland; and Lesher, of Churchville, both 15, died Saturday at the Geisinger-Community Medical Center in Scranton, Lackawanna County Coroner Timothy Rowland said.
Of the three survivors, one was a Council Rock student and two were from the area where the accident occurred, Radick said.
The Council Rock student suffered a non-life-threatenting injury and was home Sunday, Klein said.
The conditions of the two survivors were unavailable Sunday.
Autopsies on Digney and Lesher were scheduled for Monday morning, Rowland said. No information was available on Keffer.
As news of the accident spread, condolences filled Twitter pages.
"Sending all of our love, thoughts and prayers to the families, friends and entire community affected by this tragedy. Rest easy boys," read one purporting to be from the high school's women's lacrosse team.
"rip to one of my family members shamus digney. I cant believe it," wrote another person whose Twitter handle is Dani Orlando. "im in tears it feel like yesterday I saw you at uncle richies house."
A woman who answered the phone at the home of one of Digney's relatives said it was not a good time to comment.
"We're still getting our heads wrapped around it," she said.
Lesher's uncle Frank Ross said Lesher's parents, Edward and Lisa Lesher, were "pretty much out of it."
He said his nephew had just made the soccer team and was the school's business student of the month in January. Lesher also volunteered with a club involved with the Special Olympics, Ross said.
Keffer's aunt Beth Abrams described her nephew as "the kind of person who just drew people to him. Everyone who met him was better for it. He made us laugh a lot."
He was a good student and a "very accomplished athlete." She said the school lacrosse team had "decided to dedicate the season to him."
Keffer spent a lot of time this summer with his large family at Long Beach Island.
"He wasn't one of those kids who wanted to ditch his family and go to the boardwalk," she said. "He wanted to hang with his family all the time . . . He loved to play games with the family. Board games, word games."
John Hiron, coach of the boys' lacrosse team at the school, said, "It's just a tragedy all around."
Inquirer staff writer Tim McManus contributed to this article.