ROCHESTER HILLS, Mich. — The parents of a Michigan teen charged with killing four students at Oxford High School were scheduled to return to court Tuesday on charges of involuntary manslaughter.

A probable cause conference was scheduled in Rochester Hills District Court for James and Jennifer Crumbley.

Police said the Oxford, Michigan, couple was found Dec. 4 hiding in a commercial building in Detroit after warrants were issued for their arrests. They’re jailed on bond of $500,000 apiece.

Probable cause conferences typically are procedural and involve discussions between defense attorneys, prosecutors and a judge on bond and other matters.

Their son, Ethan Crumbley, is charged as an adult with murder, terrorism and other crimes.

His probable cause conference was adjourned from Monday to Jan. 7 to allow his court-appointed lawyer to review evidence including witness statements from the Nov. 30 shooting that also left six other students and a teacher wounded.

James and Jennifer Crumbley are accused of failing to intervene on the day of the tragedy despite being confronted with a drawing and chilling message — “blood everywhere” — that was found at the boy’s desk.

The Crumbleys committed “egregious” acts, from buying a gun on Black Friday and making it available to Ethan Crumbley to resisting his removal from school when they were summoned a few hours before the shooting, Oakland County prosecutor Karen McDonald has said.

They entered not guilty pleas to each of the four involuntary manslaughter counts against them at their arraignment.

They were captured in a commercial building that housed artwork. The Crumbleys’ attorney, Shannon Smith, had said the day before that the pair had left town earlier in the week “for their own safety” and would be returning to Oxford to face charges.

Detroit Police Chief James White has said the couple “were aided in getting into the building” and that a person who helped them may also face charges.

Oxford High School, about 30 miles (50 kilometers) north of Detroit, has been closed since the shooting. Students on the school’s sports teams began returning Monday to competition.

The district says it has consulted with mental health experts and law enforcement officials on the return of athletics, and the recommendation was to give students and the community opportunities to interact with their peers.

Other schools in the district were closed Tuesday out of “an abundance of caution,” the district said, after a threat was directed its middle school on social media. Online threats against other Michigan schools following the shooting at Oxford High have led to school closings elsewhere and charges.

The Oxford district also will hold its first school board meeting Tuesday evening since the shooting.