This Tuesday, May 24, 2016 photo provided by the U.S. Forest Service shows bags of trash on a boat after cleaning up a half-mile-wide swath of trash left behind by about 1,000 campers after an annual trip to Lake Shasta, Calif., by fraternity and sorority members. Shasta-Trinity National Forest spokeswoman Phyllis Swanson says it took about 25 workers five hours to clean up the weekend mess on Slaughterhouse Island in Lake Shasta on Tuesday. (U.S. Forest Service via AP)

REDDING, Calif. (AP) — A campsite that offers a serene getaway by a California lake was wrecked after about a thousand fraternity and sorority members left a half-mile-wide swath of trash, empty bottles, tents and coolers after an annual trip.

The National Forest Service said dozens of workers spent five hours cleaning up debris left behind over the weekend on Slaughterhouse Island in Lake Shasta.

Pictures on social media showed some of the mess, including several items branded with University of Oregon logos and a cooler with the Greek letters Lambda Chi Alpha.

The University of Oregon is investigating whether other campus fraternities and sororities in addition to Lambda Chi Alpha were responsible for the mess, university spokesman Tobin Klinger said Wednesday June 2nd.

The investigation won’t be easy given the large number of people there and possibility that other schools were involved, Klinger said.

“You’re going to have a variety of people, not exclusively one fraternity or sorority, not exclusively one university, not exclusively Greek, non-Greek,” he said.

Fraternities and sororities all along the West Coast take trips to the area each year, Robin Holmes, vice president for student life at the university, said in a statement.

Holmes said the mess was “disgraceful.”

“We are working with authorities to learn all we can and determine who is responsible,” she said.

The national Lambda Chi Alpha fraternity suspended the activities of its University of Oregon chapter, Holmes said.

The chapter is cooperating with the university’s investigation and will hold the people involved accountable, it said in a statement posted on the university’s fraternity and sorority life Facebook page.

The group also said it had reached out to the forest service to help with the cleanup.