As cleanup continued Thursday at the site of a pipeline leak in southwestern Minnesota, authorities said they have identified a suspect whom they believe damaged the line.

The suspect that was identified by the Lyon County Sheriff's Office has no known connection to Magellan Midstream, and authorities do not believe the leak was an act of sabotage, said Sheriff Eric Wallen. The case has been sent to the county attorney's office for possible charges.

On Wednesday night, thousands of gallons of diesel fuel leaked through a small hole in the damaged Magellan pipeline, with some of it finding its way into a drainage ditch near Cottonwood, Minn., authorities said.

Evidence of the leak first surfaced about 8:30 p.m. Wednesday when operators at Tulsa-based Magellan's pipeline control center detected a pressure drop in the pipeline, prompting an immediate closure of the related valves. The leak was halted about 10:30 p.m.

On Thursday evening, Magellan officials said in a news release that a day of cleanup involving scores of people "made significant progress recovering a high percentage of the available diesel fuel in the drainage ditch, which ultimately flows into the Yellow Medicine River."

"However, minor remnants of a petroleum sheen have passed through the containment areas along the drainage ditch," the company added. "We are continuing cleanup operations on the drainage ditch."

Until repairs on the affected part of the damaged 8-inch pipeline can be completed, the segment of pipeline between Willmar and Marshall, Minn., will remain out of service, the company said. The presence of alternative supply sources in the region means there will be no shortage of gas or diesel fuel in the area, it said.

No one fell ill from the leak, and there were no evacuations, authorities said. One minor injury was reported to a cleanup worker.