Many of the songs, collected on an account she appeared to share with her fiancé, Brian Laundrie, focus on love and heartache.
"Your woman is your angel, is your left side, is your whole life; easily the most beautiful thing in the world," one song, Matt Berry’s "Woman," begins. "She'll soothe you; she'll accuse you; she'll confuse you; she'll lose you but always be the best friend you have in the world."
Another song, "Take My Hand," is about picking up a stranger at a bar. "The Badger’s Wake" is about a badger decomposing underground.
The four Berry songs appeared on the "Mtn tops" playlist on Sept. 1. A day before that, a new list emerged titled "Selfconsumption."
Gabby Petito is pictured in provided, undated images. (Photo credit: North Port Police Department)
Petito, 22, and Laundrie, 23, an engaged pair of hikers active on social media, were road tripping across the U.S. in a white Ford Transit van, which police have recovered as part of their investigation into her disappearance. The FBI began a forensic examination on the vehicle Tuesday, North Port police told Fox News.
She was last seen in late August at Grand Teton National Park in Wyoming, according to police, and she was reported missing over the weekend after her parents hadn’t heard from her in a week.
The two had been involved in some kind of incident on Aug. 12 in Moab Utah, according to the police chief there, but responding officers did not find evidence of a crime.
"Neither Brian or Gabrielle were the reporting party," Chief Bret Edge said Tuesday night.
He returned to Florida in her van without her and has not publicly explained why – prompting her parents to plead for him to explain where he last saw her.
"The Schmidt and Petito family implore Brian to come forward and at least tell us if we are looking in the right area," her parents said in a joint statement Tuesday night.
Laundrie has not been charged with a crime or accused of playing a role in Petito’s disappearance. Police in North Port, Fla., called the case "odd" and said they wanted to speak with Laundrie.
"I think anyone would assume that the possible last person to be around her is a person of interest to want to talk with," a North Port police spokesman told Fox News Tuesday. "However, there is no crime at this point."
Authorities in New York and Florida handling the missing persons case did not respond to requests for comment on the Spotify activity
In a statement Tuesday, Laundrie’s attorney Steven Bertolino said his client’s family hoped that Petito would be found and reunited with her parents. He did not respond to repeated questions about whether the couple had broken up.
"On behalf of the Laundrie family, it is our hope that the search for Miss Petito is successful and that Miss Petito is reunited with her family," Bertolino said. "On the advice of counsel, the Laundrie family is remaining in the background at this juncture and will have no further comment."
Authorities described the missing Petito as White and about 5 feet, 5 inches tall, weighing around 110 pounds. She has blonde hair and blue eyes, and several tattoos, including one on her finger and one on her forearm that reads "let it be."
Petito and Laundrie started their trip on July 2, and the missing woman’s mother said during a Monday news conference that they had regularly been in contact until the last week of August.
"The last text I got from her was on Aug. 30," Petito’s mother, Nichole Schmidt, said. "I don’t know if that was her texting me or not."
On Aug. 19, the couple posted an eight-minute video about their cross country trip to their YouTube account, sightseeing at landmarks and beaches, camping, playing games and smiling in an idyllic montage that appeared mostly recorded on the West Coast.