Sladewski's family is devastated.
"I was bawling, I was shaking ... I'm on tranquilizers, that's where I'm at. Somebody killed my little girl," said Pat Watkins, Sladewski's mother.
Sladewski split her time between her California home, which she rented with her boyfriend, and her parents' home in suburban Detroit.
Sladewski traveled with her boyfriend, 34-year-old Kevin Klym, to South Beach for a Lady Gaga concert on New Year's Eve. Firefighters made the gruesome discovery Sunday night when they put out a trash bin fire behind an industrial building in North Miami.
"Somebody seen something, somebody knows something, and to solve this," Dave Coleman, Sladewski's ex-boyfriend, said in a phone interview with Eyewitness News.
Coleman said he last spoke with Sladewski a few days ago.
"Right before New Year's I told her I was going to Vegas with some friends. She said, 'yeah I'm going to Miami.' She was all happy about it," said Coleman.
Authorities said they have no motive for her murder.
Sladewski's boyfriend is being called a person of interest in the case. His attorney says Klym has nothing to do with the murder.
Klym reported her missing Monday, telling authorities he became separated from her at a Miami club over the weekend. He said they spent Saturday night at a nightclub, but he left alone after they argued about her heavy drinking.
Klym said bouncers kicked him out at 7 a.m., and he never saw her again. Workers at the Miami nightclub, who didn't want to be identified, told a Miami TV station that Sladewski left the club that morning holding hands with another man, not Klym.
Klym's attorney said his client is in Miami and is cooperating with police.
Coleman and one of Sladewski's neighbors told Eyewitness News that Sladewski and Klym fought often.
"I mean yeah, it was pretty hostile, but then it would calm down. Things would get crazy and things would be normal," said Coleman.
"They fought because we had the police over here quite a few times," said Michelle Lee, who lives across the street from the home Sladewski lived in with Klym. "We didn't know her all that well, and I mean not to be mean, it just ... I don't know, they were very volatile."
Sladewski's murder harkens back to last August and the violent death of model Jasmine Fiore. Fiore was found mutilated in a suitcase that had been dumped in a trash bin in Buena Park. Her boyfriend, Ryan Jenkins, reported her missing, then disappeared. Police launched a manhunt, but Jenkins killed himself in Vancouver, British Columbia, before police could track him down.