Sen. Schmidt was previously arrested last year following 911 calls from her husband.
In this latest incident, the neighbors claim the harassment lasted for more than a year in sheriff's department documents obtained by ABC 7.
The alleged victims -- a man and wife described as "close friends" of Schmidt's family -- say the trouble began in December 2010 with harassing phone calls, text messages, and emails from the state senator accusing the female neighbor of having an affair with Schmidt's husband Robert. The woman denies the charge.
Then in March of this year, the couple says Schmidt spoke to their 7-year-old son about the alleged affair, prompting the couple to call police.
And just this past weekend, the neighbors say they confronted the state senator after she photographed their vehicles while hiding in bushes.
On Wednesday, some of Schmidt's constituents reacted harshly to the allegations.
"I say you throw the book at her and treat her just as much as anybody else. Treat them equally," said Chris Fouse, Lake Villa resident.
The 60-year-old Lake Villa Republican was arrested at a Gurnee hardware store Tuesday evening on misdemeanor charges of criminal damage to property and trespassing for allegedly taking a chicken feed bag from the neighbors' property and throwing it into a nearby swamp.
The couple says they have video of the incident.
This isn't the first time Schmidt's conduct has come into question.
On Christmas Day 2010, Schmidt called 911 after her husband did.
Dispatcher: Lake County Sheriff Alison.
Schmidt: Hi, Allison. This is Suzi Schmidt, the - I was the Lake County Board chairman for 10 years. Listen, I'm having a little problem with my husband right now.
Dispatcher: Like a domestic-type problem?
Schmidt: Yes, but it's fine so if he calls you - Bob Schmidt - you can ignore him.
After that 911 call came to light last fall the state senator announced she would not seek re-election this year.
ABC7 spoke briefly with her husband Robert on the phone who declined to comment on any of the allegations contained in the police reports. He has not been charged with anything. He did confirm that he and state senator are separated and in the process of getting divorced.