A man accused four years ago of trying to burn down a North Dakota high school where he worked as principal is appealing the loss of a federal lawsuit he filed after the criminal case against him was dismissed.

Thomas Sander was accused of setting a fire March 3, 2014, that forced the closure of Trinity High School, a private Roman Catholic school in Dickinson. No one was hurt by the blaze, which was intentionally set in a filing cabinet, but it caused extensive damage. The school didn't reopen until the start of the next school year after an estimated $20 million was spent on cleanup and repairs.

Sander was charged with felony arson and endangering by fire. The case was dismissed four months later after a judge ruled that police had not read Sander his rights before an interrogation and had coerced some of his statements. Prosecutors decided not to proceed with the case without evidence from the police interviews.
Sander sued the city of Dickinson, three law officers and several other unnamed city officials in May 2015 for unspecified damages, saying his civil rights had been violated.

"Defendants' coercive tactics included, but were not limited to: sleep deprivation, intimidation, bullying, threats, deception, lies, and the withholding of bathroom facilities, food and water," his lawsuit claimed.

The defendants argued that Sander lacked evidence to prove his case, and in February, U.S. District Judge Daniel Hovland agreed, ruling in part that authorities had probable cause to arrest Sander, that they hadn't acted egregiously, maliciously or negligently, and that they hadn't intended to violate his rights. He also ordered Sander to pay $3,500 of the defendants' costs.

Sander appealed to the 8th U.S. Circuit Court of Appeals on March 7. His attorney, Ryan Shaffer, didn't immediately comment on the appeal Monday. His written arguments aren't due in court until early May.

Authorities never publicly discussed a possible motive after Sander's arrest, but Hovland said in court documents the school district had informed Sander in the weeks before the fire that his contract would not be renewed at the end of the academic year.

Hovland's order also said that a handwriting analysis concluded Sander had written a note that read, "I will bring this school to its knees," that Sander had told police he had found on his laptop after the fire. The judge also said a later confession from a student was deemed not to be credible, and the student was charged in juvenile court with hindering law enforcement.

No other arrests were made in the case. Dickinson police did not immediately comment Monday on whether the investigation remains open.