Anderson is also being investigated for another assault that happened August 15 near West Cornelia and North Marshfield.
Anderson spent 30 years in prison for rape until his parole in June. He had been jailed for numerous criminal sexual assaults in 1977.
The convicted rapist was charged in the latest crime after a cell phone he stole from his victim led detectives right to him.
Police say Anderson attacked as his victim left the Red Line stop at North and Clybourn and headed to her boyfriend's home. Investigators say, armed with a knife, Anderson forced her into her boyfriend's apartment where he held her for over an hour, sexually assaulting her before letting her go around 4 a.m.
The victim was listening to music with headphones or earbuds and did not realize a man with a knife was following her, and when she got to the door, the suspect came up behind her and held the knife to her throat, according to police.
She told him the residence was her boyfriend's home, but Anderson allegedly forced his way into the apartment and allegedly threatened to kill her and the boyfriend, who was at work, police said.
Anderson was charged with criminal sexual assault, aggravated kidnapping, home invasion and burglary in the attack on the 28-year-old woman.
She was taken to Advocate Illinois Masonic Medical Center in an unidentified condition, according to police.
The arrest of Julius Anderson has sparked a debate over prison reform after the convicted rapist was recently released only to strike again.
Anderson is a C-number inmate inmate, the designation used for those convicted of crimes before 1978 before the laws were changed.
Jennifer Bishop Jenkins of IllinoisVictims.org says that Anderson should never have been released from jail.
"The C-number inmate prisoners at this point are the worst of the worst. They need to serve out their sentences. The prisoner review board standards for release at this point should be extremely high if not impossible to obtain," said Jenkins.
Victims rights groups say that prison reform is needed.
"He has a horrendous constitutional disciplinary history including 99 major tickets, 34 minor tickets," said Jorge Montes, Illinois Prioners Review Board.
Convicted of various criminal sexual offenses in 1977, Anderson was released in June of 2009 after serving most of his time, some 30 years in prison.
On Thursday, Anderson was charged with two separate sexual assaults: one on September 1 and another on August 15. A judge denied bond for Anderson. Anderson remains in police custody.
Those who support inmates' rights to earn early release say Anderson's case proves that there has to be a better balance between public safety and the rehabilitation of prisoners.
"If we take into consideration all these different factors and think about qualified body that can look at prisoners who may be don't need to be incarcerated forever and should be incarcerated longer than their sentence that would be a preferable model. There's lots of different factors to consider," said Shaena Fazal, John Howard Association.
Anderson will be back in court in about two weeks.
The STNG Wire contributed to this report.