Glenn had turned himself in Thursday night, the same day Army veteran Delbert Belton died of his injuries.
The slightly-built youth gave yes and no answers to questions from the judge but otherwise said nothing.
Defense attorney Chris Phelps noted after the hearing that the case has gone viral on the Internet, with many people expressing strong opinions.
"The evidence doesn't indicate what happened," Phelps said, adding that eyewitnesses only reported "two kids running away."
A second 16-year-old boy, Kenan Adams-Kinard, was arrested without incident early Monday on a warrant for first-degree murder and first-degree robbery. He has a court appearance scheduled for Tuesday and will also be tried as an adult.
"The two individuals we believe are responsible for the robbery and murder of Mr. Belton are in custody," Police Chief Frank Straub said at a news conference.
The Associated Press does not generally identify minors accused of a crime but is naming the teens because of the severity of the charges.
Belton, who was wounded in the Battle of Okinawa, was beaten in his vehicle as he waited for a friend in the parking lot of an Eagles Lodge in north Spokane on Wednesday; his wallet was taken.
Straub said it appeared that Belton fought back against his attackers, which may have increased the severity of his beating.
"Our information indicates the individual fought back and that may have made this a worse situation," Straub said. Nevertheless, "I encourage people to fight back" when attacked, Straub said.
Police received a tip early Monday about Adams-Kinard's location, Straub said. Three other juveniles in the house with the suspect Monday were arrested for investigation of rendering criminal assistance, a felony.
Investigators believe the boys targeted Belton randomly. "There is no gang activity associated with this incident," Straub said.
Both suspects have criminal records for assault, he said.
"It bothers me that a distinguished World War II veteran lost his life," Straub said. But the lives of the young suspects are also likely ruined, he said.
Belton was born and raised in Spokane. He survived being shot in the leg in 1945 at Okinawa, one of the fiercest battles of the war, and went on to spend 33 years working for Kaiser Aluminum before retiring in 1982.
Belton was called Shorty by his friends because he was little more than 5 feet tall, his niece Pam Hansen said.