Jennifer Crumbley, the mother of a teen gunman who killed four people in a 2021 shooting at Oxford High School in Michigan, took the stand Thursday to testify in her involuntary manslaughter trial. Crumbley repeatedly told the jury she did not believe her son struggled with mental health issues. Lilia Luciano has the latest. "CBS Evening News with Norah O'Donnell" delivers the latest news and original reporting, and goes beyond the headlines with context and depth. Catch the CBS Evening News every weekday night at 6:30 p.m. ET on the CBS Television Network and at 12 a.m. ET on the CBS News app. Subscribe to the "CBS Evening News" YouTube channel: https://youtube.com/CBSEveningNews Watch full episodes of "CBS Evening News": https://cbsnews.com/evening-news/full-episodes/ Follow "CBS Evening News" on Instagram: https://instagram.com/cbseveningnews/ Like "CBS Evening News" on Facebook: https://facebook.com/CBSEveningNews Follow "CBS Evening News" on Twitter: https://twitter.com/CBSEveningNews Download the CBS News app: https://cbsnews.com/newsletters/ Try Paramount+ free: https://paramountplus.com/?ftag=PPM-05-10aeh8h For video licensing inquiries, contact: [email protected]