A Florida man arrested in February during an investigation into the disappearance and death of his girlfriend's teenage daughter has officially been charged with murder.

Osceola County Jail records show Stephan Sterns, 38, who was arrested on Feb. 28 on unrelated charges, was charged with first-degree murder on Wednesday in connection with the death of 13-year-old Madeline Soto.

Soto, who was found dead on March 1, was allegedly killed by Sterns sometime between Feb. 25 and Feb. 27, according to the indictment obtained by FOX 13 Tampa Bay.

"The evidence shows an individual that was entrusted to keep Madeline safe made calculated moves to dispose Madeline's belongings and place her body in a wooded area before she was ever reported missing," Kissimmee Police Chief Betty Holland said during a news conference Wednesday afternoon.

MADELINE SOTO DISAPPEARANCE: BOYFRIEND OF MISSING FLORIDA TEEN'S MOM ARRESTED, NAMED 'PRIME SUSPECT'

Sterns, who was dubbed the "prime suspect" in Soto's disappearance in February, was initially taken into custody for sexual battery and possession of child sexual abuse material after voluntarily turning his phone in to police.

A Digital Forensics Unit was able to reveal that the images and videos on Sterns' phone were "criminal and sexual in nature," the Orange County Sheriff's office said when announcing his arrest. Police did not say if the pictures and videos involved Soto.

In March, he was also charged with eight counts of sexual battery of a child under 12, five counts of sexual battery with a child aged 12 to 18, seven counts of lewd and lascivious molestation and 40 counts of unlawful possession of materials depicting sexual performance by a child.

Court documents in those cases implied Sterns may have abused Maddie for years leading up to her disappearance and death, according to FOX 13.

PRIME SUSPECT IN SOTO DISAPPEARANCE, KILLING FACES 60 NEW CHILD SEX CRIME CHARGES

While the only person charged in Soto's disappearance and death as of Wednesday is Sterns, the investigation remains active, according to Will Jay, the Homicide Unit chief for the State Attorney's Office for the 9th Judicial Circuit.

Sterns was the last person to see Soto on Feb. 26, when he allegedly dropped her off a few blocks away from her school that morning, according to police during his February arrest. 

When her mother went to pick her up at about 4:30 p.m., she learned that Maddie never made it inside the school that day.

FOLLOW THE FOX TRUE CRIME TEAM ON X

It has not yet been decided if the death penalty will be sought against Sterns, State Attorney Andrew Bain said Wednesday.

"That's a discussion that we are still going to be having for the next couple of weeks to make sure that we are making a legal decision that is appropriate in this case," Bain said when asked about the possibility of the death penalty.

Sterns remains in the Osceola County Jail with no bond.