Centennial, Colorado (CNN) -- A judge said Monday there is good cause to let Colorado movie theater shooting suspect James Holmes change his plea to not guilty by reason of insanity.
But Judge Carlos Samour Jr. said he will not rule until other matters are resolved, possibly later this month.
Holmes had offered to plead guilty and spend the rest of his life behind bars if authorities would spare his life, but prosecutors in Arapahoe County announced a month ago they would seek the death penalty.
Holmes' attorneys announced last week they wanted to change his plea to not guilty by reason of insanity, and Samour responded by giving them an opportunity Monday to show they had good cause for the change.
Samour ruled Monday that they did, after the defense attorney Daniel King said in court that defense experts have made a diagnosis supporting the plea.
King did not specify what that diagnosis was.
Holmes' trial is scheduled to begin in February. It is expected to last about four months.