Brand new article- gonna post the parts I found to be most relevant
Mark Jensen homicide re-trial: Julie Jensen's friend, acquaintances testify in court (madison.com)
Mark Jensen, according to prosecutors, killed his wife over three days in early December 1998 by poisoning her with ethylene glycol, more commonly known as antifreeze, and then suffocating her while she lay in bed dying and gasping for air in order to be with a mistress. They also allege he killed Julie Jensen out of anger over a previous affair she had with a co-worker, along with other marriage issues.
They also allege he searched the internet for ways to make her death look like a suicide and terrorized her for years with strategically placed *advertiser censored*, emails and phone calls.
Eric Schoor, the best friend of the Jensen's oldest son David Jensen, said he would hang out at the Jensen household every other Wednesday after school.
Schoor said David Jensen was normally a "very positive and energetic kid" but in the days before his mother's death he seemed "grave" and "worried."
Schoor said David Jensen told him that his mother was sick and his father declined to take her to the hospital for care. Schoor said David Jensen mimicked his mother's strained breathing for him while at school in the days before her death.
Eric Schoor, David's childhood friend
Joseph Mangi, the principal at Bradford High School in 1998, talks about interviewing the late Julie Jensen just prior to her death during the trial at the Kenosha County Courthouse on Thursday, Jan. 12, 2023.
[He] said he decided to offer her the job at Bradford, one of Kenosha County's largest schools, because she "loved working with kids" and of her previous experience volunteering at her oldest son's elementary school in the district.
However, when he attempted to contact Julie Jensen with the good news in the week ending Nov. 30 he was unable to reach her, he said.
Mangi said he called the Jensen home during normal business hours and believed Mark Jensen answered the phone.
When he asked to speak with his wife Mark Jensen said something Mangi said he found disturbing.
"His response was she's asleep and she's going to be asleep for a long time, and he laughed," Mangi said. "It was disconcerting."
A day or two later, Mangi learned she had died.
"Something wasn't right," Mangi added. 
