LIVERMORE -- Three juveniles were arrested Wednesday on suspicion of sending cyber threats to a boy who was sexually abused by former Livermore "Hummer Mom" Christine Hubbs more than two years ago.

The suspects' names were not released because they are under 18, but police said those arrested were friends of Hubbs' teenage children.

The threats against the victim began Feb. 16 on Twitter, just after Hubbs -- who was convicted in 2011 of sexually abusing the boy -- had been released from prison then rearrested for a parole violation. Hubbs, 44, served 2½ years of a five-year sentence for sex crimes against two 14-year-old boys. She was released Feb. 10, but arrested again on Feb. 15 after a parole agent found pornography in her Hayward home, a felony violation of a parole.

Hubbs was not involved in the threats against her victim, police said. Police did not disclose the nature of the cyber threats.

"We looked into whether Hubbs encouraged others or initiated the threats toward the victim," said Livermore police Officer Steve Goard in an email. "There was no Internet activity or threats to either one of her original victims while she was in prison. She got arrested (Feb. 15) and the threats began the very next morning by friends of (Hubbs') children."

Hubbs has been cleared in the cyber-bullying case, but she is not free of trouble with the law.

She remains in Santa Rita Jail in Dublin on a no-bail hold, which is standard for parole violators. A spokesman with state prisons said earlier this month that she will have a hearing on the pornography arrest to determine if she will return to prison. The spokesman was not available for comment Wednesday.

During the police investigation into the sexual assaults in late 2010, Hubbs, a mother of three, became known as "Hummer Mom" because of the giant SUV she drove around Livermore, often with the boys in the vehicle.

Contact Kristin J. Bender at kbender@bayareanewsgroup.com. Follow her at Twitter.com/kjbender.