Details of Disappearance Schweickardt was last seen at her duplex in the 5600 block of Monte Rosso Road in Sarasota, Florida on April 9, 2003. She had lived there since 1994. She has never been heard from again. She is from Germany and was in the United States on a tourist visa at the time of her disappearance. She traveled at least once a year to maintain her visa, going to Germany and Canada.
Schweickardt had rented her spare bedroom to John Alan Mellquist prior to her disappearance. A photo of Mellquist is posted with this case summary. He had only been renting the room for a few weeks, but she was in the process of evicting him and had already found another tenant, Sonja Burroughs. Mellquist was supposed to move out on April 13.
Burroughs called Schweickardt's home on that date, and Mellquist said she had a family emergency and had gone to Germany. Burroughs was concerned because Schweickardt had said she was afraid of Mellquist, and she called the police and asked them to check on Schweickardt's welfare. The police visited her home twice and both times Mellquist told them she was out of the country.
In June 2003, police found Mellquist sleeping in Schweickardt's car, a silver and black 1987 Dodge Aries with the Florida license plate number F07ILF. He said he was buying it from her. He also used her credit card eight times in April and May, and forged and cashed three of her checks.
Investigators got a warrant and searched the house in October. They found a substantial amount of blood, including drag marks in blood on the garage floor. Someone had tried to clean up with a mop. There was a bloodstained mop in the laundry room, with Mellquist's fingerprints on the handle.
Although Mellquist said she was traveling abroad, Schweickardt left her purse and passport behind at home; she would have needed the passport to leave the country.
Authorities believed Mellquist had murdered his landlady, but as Schweickardt has no immediate family in the United States, they were unable to get DNA from family members to prove the bloodstains in the house were hers. Over the course of several years, they were able to build up a DNA profile for her using personal belongings she left behind at home.
In February 2013, they arrested Mellquist and charged him with second-degree murder. He was convicted in July 2016, after a seven-day trial, and sentenced to life in prison.
Foul play is suspected in Schweickardt's case due to the circumstances involved.
- Sarasota County Sheriff's Office
Updated 5 times since October 12, 2004. Last updated December 3, 2017; details of disappearance updated.