ORANGE COUNTY, Fla. — Newly-released documents shed light on a series of alleged events and evidence against Stephan Sterns, who is accused of killing his 13-year-old step-daughter Madeline Soto.

Sterns remains behind bars on a count of first-degree murder, and numerous child sex abuse charges. This week, the State Attorney's Office announced it will be seeking the death penalty in the case.

Documents detail that child sex abuse material was allegedly retrieved from Sterns's phone. Jonathan Rose, a local defense attorney, says this is a key piece of evidence that will allow the prosecution to point to a motive.

"His attorneys will try and say that the images that may have been found on his phone will be inadmissible because they'll be too prejudicial, they're not relevant to the murder," Rose said. "Which I doubt very seriously would work. But I'm sure they'll make those arguments."

According to investigative documents, detectives found surveillance video of a car matching Sterns's heading to the trash compactor earlier in the morning at 7:35 a.m. While the man, who investigators say matched the description of Sterns, discarded trash, a female in the car sat slumped over with her mouth "ajar.”

Other video detailed in the documents appeared to show the female in the same slumped position leaving the apartment complex, detectives said.

"(The defense will) certainly make arguments that the person wearing the green shirt in the car was asleep," said Rose.

It's unknown to the public how clear the videos were, but Rose said the prosecution will be tasked with ensuring they don't initially oversell evidence to a jury.

"What's important is they're clear about what the jury is seeing, and they're honest about what the jury is going to see," he said.

Sterns reportedly told investigators that he dropped Soto off nearby the school, sometime between 8:20 a.m. to 8:40 a.m. — telling investigators he did not drop her off directly in front of the school because she was going through a "phase" and was "embarrassed of his vehicle."

Of the most notable video evidence detailed, investigators say a vehicle matching the description of Sterns’s was spotted in a parking garage of a Holiday Inn. In the video, a male exits the car and carries what appears to be a limp body from the passenger seat to the trunk, the documents said.

"That is a very compelling piece of evidence, and his attorneys are going to have a great deal of difficulty with that," said Rose.

Below is the timeline according to Sterns’ written and verbal accounts and video surveillance detailed, all of which were found in documents given to Spectrum News by investigators:

7:00 a.m.-7:15 a.m.: Sterns told detectives that he and Madeline woke up to get an early start so they could get McDonald's on the way to school.

7:35 a.m.: Video shows a male, believed to be Sterns, discarding a trash bag filled with items in the trash compactor of his apartment complex. In the video, there is a female wearing a green sweater, believed to be Madeline, in the front seat of the vehicle. The female appeared completely slumped over with her mouth “ajar.”

7:30-7:45 a.m.: Sterns says they left home and drove towards McDonald’s at 14001 Town Loop Boulevard.

7:50 a.m.: Video shows the car leaving the apartment complex through the back gate with male with a red shirt and a female wearing a green sweater. The female appeared to be sitting upright with her head slumped to her left side.

On the way to McDonald's, Sterns says Madeline slept the entire time. Once they arrived nearby McDonald’s, Sterns says he asked if she still wanted McDonald’s and she said no.

According to Sterns, he made the U-tum in a church parking lot to “sell her on McDonald’s one more time” because he was still hungry. But when she said she just wanted to go to school, Sterns says they turned around again in the parking lot of the church and continued towards school.

Sterns says he had forgotten his “gate clicker” and returned home. Instead of dropping Madeline off at school first, he said she went with him back to their home because they had “plenty of time to kill” because the school bell doesn’t ring until 9:15 a.m. This return for the gate clicker was not mentioned earlier in the interview until deputies pressed him about seeing his vehicle traveling southbound in the direction of Kissimmee.

8:19 a.m.: Video shows male with a red shirt, believed to be Sterns, entering through the front gate of the apartment complex in his car. There is still a passenger in the car, believed to be Madeline, in the same position as she was before.

Sterns says after grabbing the clicker, he and Madeline head out again towards school.

8:20 a.m.-8:40 a.m.: Sterns says he dropped Madeline off at a community south of the State Road 417 overpass. Sterns says she was going through a “phase” and was “embarrassed of his vehicle and did not like to be dropped off at the school in it.” 

8:40 a.m.-10 a.m.: Sterns told detectives he was “cruising around a bit.”

Sterns says he went to a local vape shop, but it was closed.

9:40 a.m.: Video shows a vehicle matching the description of Sterns pulling into a Holiday Inn on S. John Young Parkway. A male wearing a red shirt exits the car and opens the trunk. He opens the passenger side door and carries what appears to be a limp body to the trunk of the vehicle.

10 a.m.: Sterns says he returns home.

Due to difficulties with cameras at the rear of the complex, detectives were not able to observe any other video of the car leaving through the back gate. Investigators said they did not see the car come through the front gate from around 8:30 a.m. until 4:35 p.m.

11 a.m.: Sterns says he left home again to go to the vape shop again.

Documents show that detectives were able to find a video of a man at the vape store. The man was a white male who purchased items and left. This document does not detail what time the video was captured, or if it lines up with Sterns’s own timeline.

Sterns says he left the vape shop, and returned home.

12:45 p.m.: Sterns says he left home to run errands heading to the area of US-192.

As mentioned above, due to difficulties with cameras at the rear of the complex, detectives were not able to observe any other video of the car leaving through the back gate. 

Sterns says he visited "Coliseum of Comics” and stopped at a couple of Target stores.

Sterns said he was headed to “House Rules Games” on Oak Street and U.S. 192 but did not make it that far because he got a flat tire.

The Kissimmee Police Department later received a tip that someone observed a man matching Sterns' description changing a car tire. Deputies with the Osceola County Sheriff's Office arrived to the scene and found Soto's body in a green sweater in a wooded area.

2:35 p.m.: Sterns says he arrived home after fixing the flat tire.

4:35 p.m.: Multiple cameras captured what is believed to be Sterns arriving to the complex trash compactor in the silver Lincoln sedan. According to documents, he removed a tire, or what appeared to be the tread of a tire, and tossed it in the compactor.

Following the disappearance of Madeline Soto, deputies were able to find a tire in in the compactor, matching the tread pattern of Sterns’ rear passenger tire. In close proximity, investigators found a trash bag containing a backpack determined to be Madeline’s.