The Daily Herald Suburban Chicago, October 2, 1988, reports that there were 14 sexual assaults or attempted sexual assaults in the area since April, 1988.
Although police suspect there were more than one person involved in the sexual assaults, the majority appear to have been committed by the same man.
The map below shows where the assaults occurred. The (added by me) 305 North Lincoln Avenue address on the map where Maria Caleel lived is the approximate location in relation to the other attacks. There were instances of the assailant having a knife or other weapon during the other attacks, but none of the other victims were stabbed.
The attacks stopped three weeks previous to the date the article was written. It's unknown whether the attacks resumed
after the article was written.
Another article (attached) in the April 15, 1988 Alton Telegraph reports that a man called police from a nearby business April 13 and stated he had killed Caleel. A glass and payphone there were seized as evidence.
http://i296.photobucket.com/albums/mm176/pleasestandby2/rapesillinois_zpsq2wixwm2.jpg
http://i296.photobucket.com/albums/mm176/pleasestandby2/rapestory_zpswynqomjv.jpg
http://i296.photobucket.com/albums/mm176/pleasestandby2/glassclue_zpsudqj1p4g.jpg
Other articles show that her father, a surgeon, had filed a negligence lawsuit against the hospital that treated her because they did not immediately take her to surgery. By October, 1989, a reward of $50,000 had been offered for the conviction of the killer.