INDIANAPOLIS — One of the largest areas of focus in the Delphi investigation is a single unspent bullet found near the bodies of Abby Williams and Libby German in 2017.
That detail was revealed Wednesday when a judge ruled to release a redacted version of case documents.
According to the unsealed probable cause affidavit in the Delphi double murder case, an unspent .40 bullet was found in between the bodies of Abby Williams and Libby German.
Unspent means it was never fired.
That single bullet, investigators say links, Richard Allen, to the crimes.
An Indiana State Police laboratory analysis of Allen's gun reveals the unfired bullet was at one point, loaded in the chamber and had extraction marks on it.
"When the slide comes back like this, a round is extracted from the chamber with what's called an extractor, which is like a little claw that actually hooks on to this protruding rear edge of the cartridge, pulls it out, and then the injectors sort of kicks it out of the ejection port," said Guy Relford, Indianapolis gun expert and defense attorney. "So that claw, that extractor, grabs onto that little edge on the back of the cartridge and can leave a little mark on the shell casing, even on an unspent round through the process of extracting the unspent round out of the gun."
Testimony of a "muddy and bloody" man matching Allen's description, audio and videos are also being used as evidence.
Allen has pleaded not guilty to the murders of the girls.
Records show, he admits to visiting the trail but doesn't have an explanation for the bullet.
"It could be a malfunction of the gun. It could be a misfire or other malfunction of the ammunition. It could be someone doing it intentionally and to induce fear, and, or some factors that we haven't thought of yet," Relford said.
"The bullet puts him there. He admitted that it was his gun, he's had it since 2001 and that he hasn't loaned it to anybody," former FBI Agent Dough Kouns said.
The causes of death haven't been released to the public.
"It's not saying that they were shot by the same kind of bullet that was matched to the same kind of gun," Kouns said. "They're just saying that the spent round was there."
Questions in the highly publicized case remain.
"It's not a bullet recovered after it's been fired, it's an unspent or unfired round and that raises really interesting questions that the prosecution is going to have to deal with about why would that be on the ground at a crime scene between two bodies?" Redford said. "I think that's where a lot of the defense case is going to go, is trying to poke holes in that saying that doesn't necessarily mean that this defendant committed these crimes. I'm not saying he didn't, I'm just saying that could easily be a focus of the defense team."
Relford says the scientific evidence in the case is crucial, but that can also be disputed.
"It can be very much a battle of experts and one expert can say yes, absolutely. That round came out of that done and annexed another expert to come in and say no, you can't conclude that to what we call a reasonable degree of scientific certainty," said Redford.
Relford also says, "I think it's very important for everyone to keep an open mind because a probable cause affidavit is just one side."
The defense has pushed for the full release of the documents and has requested a change of venue due to concerns over a tainted jury.