SPOKANE, Wash. - A 17-year-old pleaded guilty Wednesday to murder in the beating death of 88-year-old Delbert Belton, a World War II veteran who survived the battle of Okinawa but was killed in a robbery outside a Washington state bar in 2013.

Kenan Adams-Kinard pleaded guilty to first-degree murder in exchange for two lesser charges being dropped. He faces a standard sentence to 20 to 27 years in prison when he is sentenced at a later date.

Adams-Kinard and Demetruis Glenn were both 16 when they were charged with severely beating Belton in his car on Aug. 21, 2013, during a robbery. The veteran died of his injuries the next day.

Get Breaking News Delivered to Your Inbox

Prosecutors subsequently charged both teens as adults with first-degree murder, robbery and conspiracy to commit robbery.

The beating death of the diminutive veteran, who was known as "Shorty," sparked outrage in Spokane.

The courtroom was packed Wednesday with family members of Adams-Kinard and Belton.

After the hearing, Pastor Ezra Kinlow spoke to reporters on behalf of the Adams-Kinard family.

Kinlow said Kenan Adams-Kinard made the decision on his own to plead guilty.

"There is nothing we can do about it," Kinlow said. "We feel that Kenan got in trouble and he has to pay."

"The family is hurt," he said.

Belton's family and friends did not talk to reporters after the hearing, which was held under tight security. But one family member talked to a newspaper on Tuesday.

Adams-Kinard "did a really terrible, terrible thing to an old man who was defenseless, and he needs to be punished for what he did," Bobbie Belton, daughter-in-law of the victim, told The Spokesman-Review.

Adams-Kinard and Glenn had been scheduled to go on trial together next week. Glenn's trial is still scheduled to begin on Monday.

Spokane County Prosecutor Larry Haskell said the Belton family supported the plea agreement.

He declined to say if the plea deal would require Adams-Kinard to testify against Glenn.

Adams-Kinard, who entered the courtroom in handcuffs and chains, repeatedly said "yes sir" as Spokane County Superior Court Judge Sam Cozza questioned him about the plea agreement.

Asked for his plea, the teenager said: "Guilty."

Under terms of the deal, Adams-Kinard would serve 20 years in prison, with credit for time already served. He would remain in a juvenile jail until age 21, and serve three years of probation after his eventual release. However, the sentencing judge is not bound by that deal, Cozza said.

Glenn turned himself in to police shortly after surveillance photos were distributed by investigators. Adams-Kinard was found by police a few days later, hiding in an apartment.

Adams-Kinard claimed in a letter to his mother that Belton was a drug dealer and had shorted them in a crack cocaine deal. Police dismissed those claims as unfounded.

Belton returned to Spokane after World War II and spent decades working at Kaiser Aluminum before retiring.