DENVER -- The two people who were arrested in the death of a 3-year-old girl were released Monday afternoon without charges, but the investigation is continuing.

Neveah Gallegos' body was found in Denver on Sept. 24 after an intensive search through Denver's Dumpsters and trash bins. The cause of her death still hasn't been determined.

District Attorney Mitch Morrissey said that Monday was the deadline to file charges or release the suspects. He said prosecutors are still waiting for autopsy reports before deciding how to proceed and which charges to pursue.

"A decision on filing criminal charges cannot be made until we have all the facts, including final results from the medical examiner that won't be back for several weeks," said Morrissey. "My office continues to work closely with the Denver Police Department in this continuing investigation."

District Attorney spokeswoman Lynn Kimbrough said that the decision to release the couple was the right decision based on the law, although it may not be a very popular decision.

"We have the opportunity to ask for an extension," said Kimbrough. "Which we did." "The first extension got us to last friday. We asked for a second extension that took us to today." "But when we became aware of the fact that we were going to need a medical examiner's final report that includes test results that won't be coming back for 6-8 weeks it became clear that we would not be able to hold them for that long."

Neveah's mother, Miriam Gallegos, 20, was arrested on suspicion of false reporting, fatal child abuse and being an accessory to murder.

Miriam Gallegos' boyfriend, Angel Ray Montoya, 22, had been arrested on suspicion of first-degree murder.

Originally, she had told police Neveah was kidnapped by two men. Police later said she admitted the girl died and her boyfriend disposed of the body.

Montoya was released from the Denver jail first -- at 3:30 p.m. -- and Gallegos was released shortly thereafter. As soon as they saw each other, they kissed and hugged. They waited for a bit in front of the jail but since they didn't appear to have a ride home, they walked across the street -- hand-in-hand -- to the throng of waiting journalists.

Reporters peppered the couple with questions about what happened to Neveah, and for an explanation to Gallegos' supposed confession.

But neither suspects talked. They crossed the street and hopped on a Regional Transportation District bus.

Because the autopsy has not been released, prosecutors still do not know if Neveah died of natural causes or if she was killed.

"I have to believe they are having a difficulty proving this is a homicide," said Craig Silverman, a former prosecutor with the Denver District Attorney's Office. "Little kids can stop breathing for several reasons." "If there was [marks from] from strangulation or stab wounds or blunt trauma then I don't think anyone would be released."

In her arrest affidavit, Gallegos said that she received a call from her boyfriend while she was at work, saying that she needed to come home right away. When she walked back to the apartment she shared with Montoya, she found that Neveah was not breathing. She told officers that she and Montoya were scared so instead of calling for help, they both decided to dispose of the body.

Gallegos told officers that they wrapped Neveah in a white plastic bag, wrapped a black plastic bag over it and stuffed the body in a blue duffel bag, according to the affidavit. Neveah was found in a plastic bag that had been dumped in a ravine about four miles from her home.