"Katherine was very sad about the verdict," a source close to the situation tells E! News exclusively.
The source could not provide any more information.
The six-man, six-woman jury decided in favor of the concert promoter on Wednesday, Oct. 2, after nearly five months of testimony.
Katherine had alleged that AEG Live contributed to her son's death by negligently hiring Dr. Conrad Murray to oversee his medical care without properly vetting the doctor or paying concern to signs that her 50-year-old son's health was in decline.
"We think this was a very important case to bring for a lot of reasons," Kevin Boyle, an attorney for Katherine, told reporters after the verdict was reached.
"We think what we've done with this case is proved some things that are important for the Jackson family and for the concert industry and the sports industry with regard to treatment by doctors," Boyle said. "We, of course, are not happy with the result as it stands now, we will be exploring all options legally and factually and make a decision about anything at a later time."
Katherine was present for the reading of the verdict.
The jury started deliberations on Thursday, Sept. 26, after dozens of witnesses testified, including Jackson's mother; his son Prince; daughter Paris (via video deposition); and ex-wife Deborah Rowe.