The mother of a 6-month-old baby found burned alive in a fire last week now has been charged as a principal to first-degree murder.

The announcement was made on Wednesday afternoon by both the Natchitoches Police Department and the Louisiana Office of the State Fire Marshal, the agencies investigating the July 17 fire in Natchitoches that killed Levi Cole Ellerbe.

Hanna Nicole Barker, 22, was booked into the Natchitoches Parish Detention Center on Wednesday. It comes one week after her son, who was just days from being 7 months old, died.

The announcement also said an additional charge would be brought against Felicia Marie-Nicole Smith, who was charged Saturday with first-degree murder in the baby's death.

What that additional charge is was not announced.

Barker's arrest comes just a day after Louisiana State Fire Marshal Butch Browning told a Shreveport radio station that more arrests can be expected in the case.

Browning made the comments during an interview with a Shreveport radio station, 710 KEEL News, on Tuesday. He said the community was reeling and still waiting for answers in the death of Levi, who was rescued from the fire and died hours later on July 18.

"We will have those answers in probably the next week or so to come, but we do expect other arrests in that case," said Browning in the interview that was posted to YouTube.

More:Natchitoches baby who died after kidnapping to be buried Friday

More:Woman charged in Natchitoches baby's death

Barker reported Levi's kidnapping through a 911 call on the night of July 17, according to the department.

She told police she had opened the door of a trailer at the Mayberry Trailer Park after hearing banging, finding two suspects who sprayed her in the face with what she thought was Mace.

She said she escaped the suspects, but then found that Levi had been taken. A multi-agency search began, but the baby was found in the fire after it was reported by a woman returning to her Breda Avenue home more than an hour later.

The fire was on the opposite side of the elevated track, away from the houses on Breda Avenue. It was about a mile-and-a-half from the trailer park.

The woman who reported the fire, Kanika Johnson, didn't know about Levi until the next day. She had thought the kids might have set the fire and reported it so it wouldn't spread.

Levi was taken to Natchitoches Regional Medical Center and later was airlifted to University Hospital in Shreveport, where he died early the next day.

More: Levi Cole Ellerbe obituary and video

And Browning confirmed during the interview that the woman already arrested, 25-year-old Felicia Marie-Nicole Smith of Natchitoches, knew Levi's family.

"This individual had a relationship with the family and certainly had access to the child, so we're still vetting through those things," said Browning. "It wasn't a random act, which is important for us to put out."

Natchitoches Chief Micky Dove wouldn't discuss a rumored relationship between Smith and Levi's mother when asked by The Town Talk on Tuesday. The department has instituted an information blackout on the case, not commenting on it beyond the two press releases issued so far.

Smith was in the Natchitoches Parish Detention Center, but online records show she was transferred on Tuesday to the Richland Parish Jail.

Browning declined to give any other information on other possible suspects when asked. The department's release announcing Barker's arrest reiterated that.

"Due to the extremely rapidly growing nature of this investigation, we must continue to restrict the information that is released," it read. "Therefore, NO FURTHER INFORMATION SHALL BE RELEASED AT THIS TIME. Thank you for your cooperation."

In the radio interview, Browning talked about why investigators were keeping a tight lid on information.

"But I think the most important thing that we have to do is get all the facts, get the family the answers that they need and get the community the answers as to what happened, because this is such a sad situation," he told the hosts, "a 6-month-old to die such a horrific and unnecessary death."

On the day after Levi was found, investigators from the fire marshal's office and the Natchitoches Fire Department were at the scene. A drone flew above the site for a few minutes while investigators walked the area.

Reaction to Levi's death has been visceral and likely will continue to be after Barker's arrest. After Smith's arrest, strangers began leaving comments on her public Facebook page.

"To burn a child alive takes a special kind of evil. I hope you get what's coming to you," read one of the more tame comments.