MARTINEZ — A Contra Costa judge on Thursday selected two doctors to assess the competency of William Shultz, effectively suspending criminal proceedings against the Discovery Bay teenager who in April stabbed to death his friend’s 9-year-old brother to “see what it felt like.”

Judge Terri Mockler made the appointments in response to a “declaration of doubt” issued by public defender Cynthia Scofield, Shultz’s attorney, in a hearing Monday. Shultz, 18, is charged with murder, robbery and the special circumstance of lying in wait.

The doctors’ evaluations are scheduled to be submitted at a hearing on July 27.

“By legal standards, what qualifies for competency is a relatively low threshold,” said Contra Costa Deputy District Attorney Simon O’Connell, who is prosecuting the case. “The evaluation will explore whether Mr. Shultz can assist in his own defense. Does Mr. Shultz know what he’s charged with? Does he know who his lawyer is? Can he, in his own words, explain the role of the judge, the jury and the prosecutor?”

Shultz seems to know this much about his lawyer: He wants her replaced. The defendant on Thursday made a Marsden motion, a request to the court to have his attorney removed from the case. That motion, closed to the public, was scheduled to be heard later Thursday.

Shultz also questioned the need for his competency to be assessed. Which is why, O’Connell said, two doctors were appointed instead of one.

Shultz was seen by a mental health professional the day before the stabbing. He was released and sent to his home, where he said he had an argument with his mother. This led to him spending the night at a friend’s house, where on the morning of April 26 he stabbed Jordon Almgren as the boy slept in his bed.

He admitted the killing the following day in a jailhouse interview with this newspaper.

“I do have remorse for what I did,” said Shultz, who has a brother around the same age as the victim. “But there’s a reason for everything that happens.”

After Shultz’s first court hearing, Contra Costa Chief Public Defender Robin Lipetzky said, “There’s no question in my mind that mental health was the main factor here.”

Contact Gary Peterson at 925-952-5053. Follow him at Twitter.com/garyscribe.