MINNEAPOLIS (WCCO/AP) — Authorities confirmed Friday that bones found in a Crystal couple’s backyard belong to an infant boy who was born in 2008, but said they have no evidence at present to bring charges in the death. They were, however, charged with misdemeanor counts of domestic assault.

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Hennepin County Attorney Mike Freeman said the suspects — a 30-year-old man and 28-year-old woman — would be released Friday. But Freeman said the investigation continues, and charges could be filed weeks from now.

“Obviously if we had sufficient evidence to prove beyond a reasonable doubt that a crime had been committed, I’d be sitting here issuing and explaining a criminal charge. We do not have that,” Freeman said. “Under the rules they’ve got to be released.”

Authorities learned of the baby’s death Tuesday, after officers in Crystal began investigating a domestic incident. Hours later, the man walked into the Crystal police station and told authorities a baby was buried in his backyard, Chief John Banick said.

Banick said he couldn’t provide details about the domestic incident and who it involved. He said the man gave police enough information to pinpoint where they should start digging, and bones were unearthed on Thursday.

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Those bones were determined to be those of a 30- to 38-week-old boy born in August 2008 in the couple’s home, Banick said. Authorities wouldn’t confirm whether the boy belonged to the couple. Banick said it seemed no one was aware the woman was pregnant.

“We don’t know, as I speak, whether the baby was alive when it was born. We don’t know whether the baby was alive when it was buried,” Freeman said. “This is a complex case, involving allegations that are a few days old, of a crime that took place a number of years ago.”

Banick said police hadn’t been called to the house until this week, but have since learned that the man and woman were physically abusive to each other in front of their children. The couple’s 10-year-old daughter and 7-year-old son have been placed outside the home for the foreseeable future, Freeman said.

The phone number for the couple’s Crystal house had been disconnected. Another number listed under the man’s name had a full voicemail box, and a message could not be left.

The couple is now in custody on the domestic assault charges, which have no bearing on the investigation into the cause of death of the infant.

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