The parents of two of the defendants in a Somali-American conspiracy case allegedly knew that their sons planned to leave the U.S. to fight with terrorists in the Middle East, according to transcripts of secret wire recordings released by federal prosecutors on Wednesday.

Mohamed Farah, whose detention hearing is scheduled for Thursday morning in federal court in Minneapolis, told another alleged conspirator that in mid-April his mother knew of his impending plans to travel to Syria, according to the recordings made by a confidential informant, a friend of Farah's who was working for the FBI.

"She knows where I'm going, bro, that's the thing … " Farah is quoted as telling co-defendant Abdirahman Daud. Later that day, Farah stated that he "didn't believe his parents would report him missing after he was gone," according to the motion that prosecutors filed arguing why he should not be released pending trial.

Farah's grandmother also may have known of his plans, according to the transcripts. In a conversation recorded by the informant, two other defendants spoke about Farah's family and the plans that the young men were making to leave the country. "His grandma told him, 'We'll give you $5,000 if you find a way out,' " according to a taped conversation that Guled Omar is said to have had with Zacharia Abdurahman back in March.

Farah also threatened to kill FBI agents if his plans fell through, those transcripts show. "If there's no way out … If our backs are against the wall, I'm gonna go kill the one who punks me. You know the one. Everybody has that one fed," Farah told the informant.

Father: 'That's a lie'

Farah's father, Abdihamid Farah Yusuf, denied the allegations and spoke on behalf of his wife, Ayan Farah. "That's a lie," he said. "How can I support my son for any terrorist activity?" He said that his sons had been followed by FBI agents for more than a year and that they felt they were being unfairly targeted.

In an interview last week, he said he believed his son Mohamed threatened to kill FBI agents in a moment of intense frustration. "They showed him the heat," he said of the FBI. "Mohamed got hot. If you push a person — he's a 20-year-old kid — you're going to explode."

A cooperating defendant

Farah and his brother Adnan Farah are among the six men who had been meeting at least since spring 2014 to find ways to leave the U.S. and fight for the Islamic State of Iraq and the Levant (ISIL), according to federal charges.

Significantly, prosecutors on Wednesday publicly cited for the first time the ongoing cooperation of a related defendant who pleaded guilty in February to supporting terrorism. That defendant is the only person to have pleaded guilty, and his cooperation shows that the government has been able to go beyond relying only on a confidential informant — using a defendant who once actively participated in the conspiracy and has inside knowledge of all of the defendants' activities.

That defendant, Abdullahi Yusuf, of Inver Grove Heights, was stopped by FBI agents from boarding a flight from Minneapolis to Turkey in May 2014. He was minutes away from boarding the plane when agents began to question him.

After pleading guilty, Yusuf was placed in a halfway house under an experimental plan approved by Chief U.S. District Judge Michael Davis. The judge agreed to allow Yusuf to enroll in a program run by Heartland Democracy that is designed to rehabilitate young people who have become disconnected from their communities. Yusuf was taken back into full custody after committing an undisclosed violation in late April.

Prosecutors do not identify Yusuf by name, only as a "cooperating defendant" who has described Farah's role and the roles of other alleged conspirators "in hopes of a reduced sentence."

Tripped up in San Diego

Farah is the last of the six defendants to make an initial appearance before Davis. Farah was arrested with Daud in San Diego by FBI agents on April 19. Farah, Daud and the informant had traveled from Minneapolis to California, in hopes of crossing into Mexico after buying fake passports. From there, they planned to catch a flight to Turkey, then cross into Syria, according to prosecutors.

In November 2014, Farah and three friends attempted to flee the U.S. by taking a Greyhound bus from Minneapolis to New York, in hopes of flying from JFK Airport to Europe, then making their way to Syria, prosecutors say. That attempt failed, but not before one of Farah's fellow travelers was taken off a plane before the aircraft departed the gate.

Even though he failed to make it out of the country, Farah later described how he felt liberated at the attempt, according to the wire transcript. "I can tell you one thing, when I went on … Greyhound, Allah, it was the best feeling in my life," Farah said.

Staff writer Abby Simons contributed to this report.

Paul McEnroe• 612-673-1745