Pat Johnson has plead guilty to four counts of aggravated assault with a deadly weapon Thursday in the Interstate 35 rock throwing incidents.

He will be sentenced to 40 years in prison, which will run concurrently to his 99-year sentence for aggravated assault of a child.

Johnson had tried to plead guilty in the morning, but was dismissed from the court over conflicting statements Johnson had made regarding his guilt. In order to get to this deal, the prosecutors agreed to drop the seven other charges against Johnson.

Pat Johnson was arrested in June 2016, almost two years after the rock throwings began. According to KVUE's partners at the Austin American-Statesman, Johnson appeared in court Thursday morning and indicated he was guilty on four felony charges. He added he wanted to plead guilty only so he could be transferred to another facility to get proper treatment for a medical condition.

Judge David Crain ended the hearing and prevented Johnson from making a plea.

Johnson was sentenced to 99 years in prison in 2016 after being convicted on an unrelated charge of aggravated sexual assault. Johnson was offered a plea deal in the rock-throwing cases in 2016, but opted for a jury trial. His trial is currently set to begin in June.

In October 2016, Johnson confessed in a series of jailhouse letters sent to KVUE and the Austin American-Statesman.

This is a developing story and will be updated with more information.