OKEECHOBEE — The image of a shackled 17-year-old shuffled across their big-screen television Tuesday evening as Roy and Rebecca Johnson got their first look at the youth charged with murdering their 19-year-old daughter.

"That's him," Roy Johnson told his wife as the watched the newscast. "They took him to the jail today."

Mark Anthony Alvarez was formally charged as an adult Tuesday with killing Elizabeth Johnson and her boyfriend, Curtis Tenney, 18, on Jan. 8. A grand jury will meet next month to decide whether the second-degree murder counts should be upgraded to first-degree with the possibility of a death sentence.

"We're glad he was caught, but we're sad for his family because now they're going to lose their son," Rebecca Johnson said.

The couple were found dead in the charred remains of Johnson's Mustang. Investigators won't say how they died, but the parents were told they were shot. There are mentions of a gun sprinkled throughout a heavily redacted arrest affidavit.

Okeechobee sheriff's investigators said Alvarez confessed to the killings but they would say nothing about his statement or any possible motive for the killings. Records with the Florida Department of Law Enforcement show Alvarez with juvenile arrests for marijuana possession and resisting officers.

He was picked up Monday night on a probation violation before being charged with killing the Johnson and Tenney.

Unusual secrecy has surrounded the investigation, which officials say has not ended with Alvarez's arrest.

Investigators and prosecutors persuaded Circuit Judge Sherwood Bauer to order much of the information in the lengthy arrest affidavit sealed from public view. Assistant State Attorney Tom Bakkedahl said releasing more could harm the case.

"We have been pulling records, phone records, tracking down leads," he said Tuesday. "This particular individual they have in custody, we have been looking for since the beginning."

Paragraphs and pages of the arrest record are blacked out, but a few clues are sprinkled among the sentences that remain.

There are several references to Alvarez's alleged gang ties, including a mention to his being a member of a Folk Nation gang. Folk Nation isn't a specific gang, but an umbrella group of gangs across the nation and perhaps worldwide.

In one section, an unidentified witness told investigators he heard Tenney got into an argument with Alvarez and Alvarez's brother about two weeks before the killings. He didn't know what it was about, but said people were yelling and wanting to fight.

In another section, a witness comments on what Alvarez was wearing and that he put a gun in his pocket. Part of the paragraph is blacked out and it isn't clear when that happened.

Jim Tenney said his son, Curtis, and Alvarez were friends for years. On the night Curtis died, he told his dad he was going to see Alvarez about returning some video games. "Your closest friend can be your worst enemy," he said.

Family members had a vigil for Tenney Tuesday night at a relative's home in Palm Beach Gardens.

Tenney and Johnson's relationship was fairly new but had the potential to become serious, family members said.

Tenney worked as a metal framer for his father's construction business. He was a hard worker and a good one, his dad said.

"He was my right hand and now my right hand is gone," he said.