Before detectives found it inside a car in Colorado, before a St. Petersburg surveillance camera captured it hanging from Christie New's neck hours before she was gravely wounded, before it was salvaged from the bottom of the ocean, police believe the medallion was part of a treasure bound for Spain in 1622.

Except the galleon Nuestra Señora de Atocha sank off the Florida Keys, trapping its crew and cargo on the sea floor. There, the ship sat for centuries until it was discovered in 1985 by treasure hunters.

Now, 396 years later, that medallion has become a key piece of evidence in the unsolved death of the 43-year-old mother.

The Spanish coin has also become a mystery unto itself.

• • •

New, the youngest of five children, came of age in Chambersburg, a small town on the Pennsylvania side of the Maryland border.

She loved animals and had a passion for rescuing them, especially dogs, cats, a potbelly pig and even possums, her sister Deanna New told the Tampa Bay Times in March.

Horses, though, were closest to Christie New's heart. She was an equestrian, competing in hunter/jumper competitions throughout the southeastern U.S., the sister said, and she owned a horse in Ocala.

As an adult, Christie New made her way to Florida, splitting her time between Key West and Morgantown, N.C.

She spent her last days in St. Petersburg.

New was found March 1 in Lake Maggiore Park by a St. Petersburg park worker. Her moans caught his attention. He dialed 911.

She was pronounced dead six days later, on March 7.

Now, in new court records filed in Pinellas-Pasco Circuit Court, detectives reveal new information about her final hours, how she died and the direction the investigation into her death has taken.

• • •

The night of Feb. 28, New was staying with a man named Adam Welch in room 156 at the Knights Inn St. Petersburg Tropicana, 2595 54th Ave. N.

Welch told investigators that the last time he saw New, she was with a man from room 160.

That man had tattoos all over his face.

Hours later, at about 3:30 a.m. on March 1, Welch said he received a notification on his cell phone that someone tried to use his debit card at an ATM about six miles from the Knights Inn.

Investigators pulled the surveillance video from that ATM. They saw Christie New using the machine, her distinctive medallion around her neck.

She was found about eight hours later, in the park, mortally wounded.

The cause of death, according to the Pinellas-Pasco Medical Examiner's Office: a gunshot wound to the head.

• • •

Motel records revealed a woman named Monica Fulse had booked room 160 the night of Feb. 28.

She was in a relationship with a man named Joseph Nieves Deleon, 29. When detectives plugged that name into the Florida's Department of Correction's website, what popped up was a photo of a man who's face was covered in tattoos.

He had been arrested in Marion County in 2010 for molesting a child. He was convicted and sentenced to more than six years in prison.

He was released in May 2017 as a registered sex offender, Florida records show. Corrections records show he has 26 tattoos total.

The St. Petersburg detectives investigating New's death said they realized Deleon was a suspect in the armed robbery of a 7-Eleven that took place at an undisclosed time.

That robbery was being investigated by the federal Bureau of Alcohol, Tobacco, Firearms and Explosives. ATF agents had already obtained an arrest warrant for Deleon and a search warrant for his car, a red 2003 Chevrolet Impala registered to Fulse.

St. Petersburg detectives and an ATF agent decided to arrest Deleon together. They flew to Fort Collins, Colo., on May 8, and found Deleon and Fulse.

Investigators asked Deleon what happened to New back on March 1.

Deleon said he took her to an ATM and then dropped her off somewhere else — but not the Knights Inn, he specified.

When investigators searched the Impala, they said they found New's medallion. Deleon said she gave him the Spanish coin to pay for narcotics.

Deleon was arrested on the federal warrant and brought back to Pinellas on June 19, when he was booked into the county jail.

He remains there, held on the federal warrant.

• • •

The Nuestra Señora de Atocha set sail from Havana, Cuba on Sept. 4, 1622, according to the Mel Fisher Maritime Museum in Key West. The most heavily armed vessel of the 28 ship flota, it sailed last to prevent an attack from the rear.

Bound for Spain, the Atocha carried treasures of the New World, including 24 tons of silver bars plus gold, indigo and tobacco.

Its manifest also included silver coins.

Just hours after the flota embarked, it was overtaken by a hurricane. Eight ships sank, including the Atocha.

Its treasure remained hidden until 1985, when the Fisher family discovered it in the Florida straits. Now it is the main attraction at their museum.

Coins found aboard the Atocha are valued at between several hundred dollars and tens of thousands of dollars, depending on their condition.

Whether New's coin is authentic is another mystery. Police believe it is. They said it was in a gold setting and featured a three-masted schooner, according to court records. Detectives think it's worth about $10,000.

Dealers at the Mel Fisher's Treasure Stores in Key West said that description didn't sound like an authentic Atocha coin. They said it could be a coin minted from salvaged materials aboard the galleon, but then it may not be worth the $10,000 cited in court records. The store has no record of selling New a coin.

Police records do not say how New came to possess the coin. Her family did not return calls for comment last week.

• • •

Deleon does not face any charges in connection with New's death.

Detectives asked a judge to grant a warrant that would allow police to obtain and test a DNA sample from Deleon so that it can be matched to DNA found on New's clothing.

A judge obliged, granting the detective's request on Aug. 9. The next day, they took a sample of Deleon's DNA.

The warrant does not reveal the result of that test.

The Times asked if Deleon is a suspect in New's death.

Police said they could not discuss any suspects in this case.

Times senior news researcher Caryn Baird contributed to this report. Contact Josh Solomon at (813) 909-4613 or jsolomon@tampabay.com. Follow @ByJoshSolomon.