An Illinois man convicted of killing his first wife more than 20 years ago shot and killed his second wife and her teen son Monday before turning the gun on himself.

Police were called to the Wilmette home of Richard Wiley after his wife Kathryn Wiley-Motes failed to show up for work on Monday morning, MyFOXChicago reported. After forcing their way into the home, police found the bodies of Wiley, Wiley-Motes and her 17-year-old son Christopher Motes.

After a preliminary investigation, authorities determined that Wiley-Motes and her son were killed sometime Saturday afternoon, and Wiley shot himself on Sunday evening.

Wiley, 55, was released from prison in 2000 after serving 15 years for the murder of his first wife in the mid-80s. At the time, he was diagnosed with intermittent explosive disorder and also battled a drug and alcohol addiction.

Relatives told MyFOXChicago that Wiley-Motes knew about her husband’s past but thought he was a changed man.

Authorities said they found they murder weapon, a sawed-off Civil War replica firearm, next to Wiley's body in a second floor bedroom. The weapon was believed to have belonged to Christopher Motes, a Civil War enthusiast. Investigators also found a lengthy, handwritten suicide note written by Wiley, but did not discuss its contents.

Kathryn Wiley-Motes worked at the First Presbyterian Church in Wilmette, which was located right next to the home where the murders occured, MyFOXChicago reported.

Christopher Motes, a senior at New Trier Township High School, was working toward becoming an Eagle Scout and was very active with the church.

The Cook County medical examiner's office has begun autopsies.

Click here for a video report from MyFOXChicago.com.

The Associated Press contributed to this report.