Raegan Day’s dark blue Chevy Camaro was her pride and joy, and she worked multiple waitressing jobs to pay for it, according to her stepsister.

But last month, the gleaming sports car became the motive for her murder and that of her friend, Dustin Hartline, according to the St. Tammany Parish Sheriff’s Office.

It’s also where their bodies were found 19 days after they disappeared. The Camaro was found submerged in the East Pearl River in an effort to cover up the killings. Hartline's body was in the trunk. Day's was inside the car.

Four people were arrested Tuesday, booked on two counts each of first-degree murder.

“This was a carjacking gone bad,” St. Tammany Parish Sheriff Randy Smith said Wednesday. “They planned this, premeditated this and met these two individuals on Salmen Street off Brown’s Village Road in East Morgan subdivision. They had masks on, they had guns, and to steal a 2011 Chevrolet Camaro, they used force.”

Brittney “Beezy” Savell, a 25-year-old Slidell woman, was an acquaintance of Day’s and contacted her to meet to discuss the possibility of buying the Camaro, Smith said.

Day and Hartline went to the meeting Feb. 15, the last day they were seen alive.

According to St. Tammany Parish Coroner Charles Preston, the two were shot in the head. Day, 20, was shot once in the front and again in the back of the head. Hartline, 28, was shot once in the back of the head, he said.

In addition to Savell, deputies arrested Jason Landry, 18; Derrion Lemoine, 22; and Steven “Stevie” Olivieri, 27.

Smith said Olivieri had an extensive rap sheet, but the others had minor records.

Three guns were recovered, two of which were used in the slayings, Smith said. He would not say which of the suspects are believed to have fired the weapons.

Lemoine has been booked with an additional count of being a felon in possession of a firearm.

Both Olivieri and and Lemoine were already incarcerated in the St. Tammany Parish Jail on Tuesday when they were arrested on the murder counts. 

Olivieri had been booked March 1 on counts of manufacturing and possessing a bomb after an “explosive device” was found at a home “during the early stages of the investigation,” according to the Sheriff’s Office. 

Landry and Savell were arrested at a home in Waveland, Mississippi, where they fled following the crime. 

Smith said family members filed a missing persons report on Feb. 16. Foul play was suspected, and the Sheriff’s Office began investigating immediately.

“When you lose two phones without any trace ... it’s not a good sign,” Smith said.

Investigators following up on a tip went to the Salmen Street address, a remote and wooded site with an abandoned trailer on the property. That's where they found a probable crime scene, Smith said.

Assisted by the Sheriff’s Office dive team, detectives began to search ponds, waterways and bayous in a 7-mile radius.

When the Sheriff’s Office received another tip that the vehicle might be near the East Pearl River Boat Launch, they focused their efforts there, pulling up the vehicle about 4 p.m. Monday and finding the bodies inside.

The vehicle was taken to the Coroner’s Office in an effort to recover as much evidence as possible from bodies, which had been underwater for more than two weeks, Preston said.

Bullet fragments were recovered from both Day and Hartline, he said. The investigation is continuing, and additional arrests are possible.

Day’s stepsister, Nicole Gallagher, described the Slidell High School graduate as a sweet, giving person, who was loved by everyone. She was passionate about animals and had dreams of going to school to study veterinary medicine.

Day, who was an only child, went to live with Gallagher's family following the death of her father, she said.

“She would give you the shirt off her back," she said. "She loved my kids, and my kids loved her.” 

Gallagher said she knew Hartline well, and thought he was a “great guy.” When Day needed a place to live with her menagerie of pets, the construction worker allowed her to move into his Pearl River home.

Gallagher said she does not know why Day would have been selling her car unless she could no longer afford it. And she’s angry that those “who don’t want to get a job to pay for it,” took two lives.

“The people who did this, I hope they never see the outside of a jail cell,” she said.

Follow Sara Pagones on Twitter, @spagonesadvocat.