Details of Disappearance
Denise was employed as an animal keeper at Wild Animal Park in San Diego, California in 2000. She and her husband, U.S. Marine Corps Staff Sergeant Charles Vasseur, resided in the 1500 block of Shadowridge Drive in Oceanside near Vista, California.
Charles said he saw his wife for the final time at approximately 5:00 a.m. on September 22, 2000 as he departed for work. Denise told Charles she planned to spend that night at Wild Animal Park for a sleepover event with a girlfriend. She was carrying her sleeping bag and an overnight bag at the time. Denise never returned to her residence and has not been seen again.
Authorities learned that her co-worker, Patrick J. Hamilton, disappeared on the same day as Denise did. Charles stated that Denise often carpooled with Hamilton in the fall of 2000. They were having an affair, and Denise apparently went to his house to end the relationship on the day she vanished.
A warrant was issued for Hamilton's arrest and authorities apprehended him on September 27. Hamilton had attempted to flee from the officers at the time, but he was arrested south of Gilroy, California. He also tried to overdose on prescription medication while in police custody.
Hamilton confessed to Denise's murder in November 2001. He pleaded guilty to second-degree murder and agreed to assist authorities locate her remains. Hamilton said that Denise had wanted to end their relationship. He said he refused to allow Denise to leave his residence on the day of her disappearance.
Denise eventually hit Hamilton in an effort to escape and an altercation ensued. He claimed he accidentally strangled her during the fight and buried her body in the Anza-Borrego Desert.
Hamilton led authorities to several locations in and around that area during November 2001, but Denise's remains were never located. Investigators suspended the search by the end of the month.
Hamilton was sentenced to 15 years to life in prison in March 2002. He attempted to change his plea in December 2001, but the sentence was imposed nonetheless.
Authorities have been unable to locate Denise's body, despite extensive searches throughout various desert areas in California. She and Charles met in Africa; she was a volunteer for a primate organization and he was on embassy duty in the region at the time.