Jurors resume deliberations Tuesday in the first ISIS connected terror trial.
Abdul Malik Abdul Kareem faces several different counts, including conspiracy.
One witness is considered a "confidential informant," a person who plays a key role in investigating and building a case against terror suspects.
"It's like playing with fire. The results are of significant value,” said Patrick Tortorici, NAU terror expert.
But confidential informants are a necessary evil to win the war on terror. They have played a key role in two Valley cases.
"Thing is, I was trying to help because they were talking about killing people," said Dalba Deng, a paid informant.
But his intel wasn't enough for the judge to consider Elton Simpson a threat.
And, five years later, Simpson went on to carry out the Garland, Texas, attack. He and his accomplice gave their lives for the ISIS cause.
That's when informant number two --Stefan Verdugo-- stepped up and gave up the alleged mastermind -- Abdul Kareem.
"Fish and bait. Give him the bait and let him reel himself in," Verdugo said.
But Tortorici says it's not lost on government that informants always have a motive.
"It is rare that a human intel source is unsullied. These are morally ambiguous people," Tortorici said.
He says tips cannot stand alone. They must be cross-checked with other intel. And while investigations might start out with the help of the informant, Tortorici says, strong cases will stand alone.
"The place you want to get eventually is that you can take them out of the investigation," Tortorici said.