Delphi murder suspect Richard Allen, who has been charged in the 2017 slayings of teens Liberty "Libby" German and Abigail "Abby" Williams, may not have acted alone, prosecutors said Tuesday in court.

In a major break in the case, Allen, 50, was arrested and charged with two counts of murder for killing German, 14, and her best friend, Williams, 13, last month.

At a bail hearing Tuesday, Carroll County Prosecutor Nicholas McLeland asked Indiana Judge Fran Gull to keep the affidavit sealed.

She said she'd decide whether to release it at a future date, FOX59 reported.

DELPHI MURDERS: WHAT TO KNOW ABOUT THE 2017 KILLINGS OF LIBBY GERMAN AND ABBY WILLIAMS

Richard Allen wearing a beige coat and yelling pants.

Delphi murder suspect Richard Allen is escorted into court Tuesday, where a judge set a bail hearing for Feb. 17. He's accused of the double slaying of Libby German and her best friend Abby Williams. (WXIN)

McLeland disclosed for the first time publicly that Allen may not have acted alone in arguing that the document should remain secret to not compromise the investigation, according to the local news site.

He added that releasing the affidavit, which outlines their theory of the case, could lead to the harassment of witnesses, who are named in the document.  

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Allen's attorneys asked the judge to set a bail hearing, which she granted. The attorneys argued that the sealed affidavit shows how thin the case is against their client.

The bail hearing is set for Feb. 17. 

After Allen's Oct. 26 arrest, the Carroll County Prosecutor's Office requested the sealing of the affidavit, and charging documents, which was granted – an unusual move in a murder case.

Richard Allen booking photo

Authorities announced Monday the arrest of Richard Allen for the murders of Libby German, left, and her best friend, Abby Williams, in February 2017. (Indiana State Police)

But Indiana State Police Superintendent Doug Carter told FOX59 that he does not believe their investigation would be undermined by unsealing the documents. Police have not released any information about the evidence that led to Allen's arrest after nearly six years.

The local married father has no criminal record and had been working as a pharmacy technician at a CVS in Delphi – a town of 3,000. 

In a desperate handwritten letter to the court two weeks ago, Allen requested a public defender.

Richard Allen wearing a beige coat and orange jail issue jumpsuit.

Delphi murder suspect Richard Allen requested a public defender two weeks ago. (WXIN)

"I, Richard M. Allen, hereby throw myself at the mercy of the court. I am begging to be provide [sic] with legal assistance in [sic] a Public Defender or whatever help is available," the note reads.

"At my initial hearing on Oct. 28, 2022, I asked to find representation for myself. However, at the time I had no clue how expensive it would be just to talk to someone. I also did not realize what my wife and I’s [sic] immediate financial situation was going to be."

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In the wake of his arrest, his wife had to quit her job for her own safety, the letter states. 

The teen girls disappeared Feb. 13, 2017, after going for a hike on the Monon High Bridge Trail. Their bodies were found the next day.