A lawyer for a 22-year-old man accused of shooting 10 people to death at a Colorado supermarket in March is raising questions about whether he is mentally competent to proceed with the case, according to a notice filed in court Wednesday.

Details on the concerns about Ahmad Al Aliwi Alissa’s mental health and how it might affect his ability to understand and participate in court proceedings are not known because the motion is sealed as required under state law.

However, a notice that such a motion was filed and the judge’s initial response is public.

Judge Ingrid Seftar Bakke said she would consider the issue at a previously scheduled court hearing Monday to determine whether there is enough evidence for Alissa to stand trial.

Shannon Carbone, a spokesperson for District Attorney Michael Dougherty, said prosecutors expected the hearing on the evidence to go ahead as planned.

Alissa’s attorney has previously said he has an unspecified mental illness.

A defendant’s ability to understand and assist in their defense is a separate legal issue than a plea of not guilty by reason of insanity, which hinges on whether someone’s mental health affected their actions when a crime was committed.

Raising the issue of competency has the potential to delay proceedings. Under state law, proceedings that require defendants to participate and assist their lawyers in defending them must be suspended if they are deemed incompetent. But hearings before a case goes to trial that do not require their participation can proceed.

(AP)