Sullivan, 35, a Navy veteran, looked downcast after hearing the verdict, but otherwise showed no emotion.
The 7-man, five-woman jury acquitted him of first-degree murder.
San Diego Superior Court Judge Albert Harutunian III set sentencing for April 13. He changed Sullivan’s $2 million bail status to no bail, but he had never been able to post bond since his February 2018 arrest in Delaware.
Deputy District Attorney Jill Lindberg said Sullivan faces 15 years to life in prison for the murder plus one year for the use of a knife. The 32-year-old victim had been stabbed to death.
“Everybody was very open with their opinions,” said one juror afterward.
“The DNA evidence wasn’t hard to listen to,” said another juror.
One juror who faced both attorneys in the hallway afterward told them “I think both of you did a really nice job.”
The couple met in Virginia where Sullivan was in the Navy before they moved to San Diego and had two children. He was honorably discharged.
Marcus DuBose, who represents Sullivan, went back into the courtroom to confer with him and could not be reached for comment afterward.
“I really appreciated the jury’s time and respect the decision,” said Lindberg afterward.
Left unanswered is where the body was kept for two years before a man walking his dog found it on the shoreline at 2600 Farragut Road at Liberty Station on Oct. 6, 2016. The body was decomposed and it likely was placed there in October 2016.
Elizabeth Sullivan vanished two years previously and was the subject of a missing person’s investigation. Detectives stopped by the couple’s home and could not find any trace of her, though a detective noted there was an empty freezer in the basement that had its power on.
Lindberg argued at trial the body may have been in that freezer or possibly in the attic where a knife was found that had both DNA traces to both Matthew and Elizabeth Sullivan.
Her body was also found on the very same day in 2016 that Matthew Sullivan, his two children, his parents, and a new girlfriend moved out.
Investigators found a lot of Elizabeth Sullivan’s blood in numerous spots in her bedroom. DeBose said to jurors that Elizabeth Sullivan had a habit of cutting herself that caused her to bleed.
DeBose told jurors that his client found his wife had broken a mirror and stabbed herself in the arm, causing blood to get on the carpeting. DeBose said that in his opening statement but did not present any evidence of that as Matthew Sullivan did not testify.
Lindberg presented evidence of the purchase of carpet cleaner by Sullivan around the time she disappeared.
The couple’s children are being raised by their maternal grandparents.
DuBose argued to jurors there was no evidence the body was in the freezer or attic as there was no discoloration or odors to anyone.
DuBose told jurors the prosecution’s case “has holes all over the place” and asked for an acquittal.
Lindberg showed jurors the knife in an evidence glass box, saying “that’s the murder weapon.” She said Elizabeth Sullivan was stabbed at least five times, with nicks on her rib bones.
Lindberg said he “was upset with his wife,” and noted her nose was also broken.
Jurors did not request to hear read back from any of the trial’s 32 witnesses. The trial began Feb. 21 and jurors sent no notes or questions to the judge during deliberations.
The case ended a week earlier than anticipated.