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A Brooklyn Park man faces murder charges for allegedly beating a 7-month-old to death, days after he found out he wasn't the baby girl's biological father.

Chris Marquis McMorris, 24, allegedly inflicted 11 rib fractures and a lacerated liver on the child when she was left in his care last March, according to second-degree murder charges filed Friday in Hennepin County District Court.

It's the second time this week that Hennepin County Attorney Mike Freeman has filed murder charges in a case involving the violent domestic assault of a baby. On Tuesday, 21-year-old Cory Morris was charged with second-degree murder after police say he beat his 4-month-old daughter to death because she wouldn't be quiet. He was watching the child while the mother was at work.

According to the criminal complaint against McMorris:

McMorris called 911 around 9:15 a.m. on March 24 to report that a child in his care was not breathing. Authorities arrived within minutes and began performing CPR on the unresponsive baby, who had deep bruising on her face. She was taken to North Memorial Medical Center in Robbinsdale, where she died within 90 minutes.

An autopsy by the Hennepin County medical examiner found that the infant died from blunt-force injuries to her abdomen.

Just three days earlier, McMorris' girlfriend — the baby's mother — had received the results of a paternity test confirming that McMorris was not the biological father. That's when signs of abuse began to appear.

When the mother dropped her baby off at day care that morning, staff members noticed two burst blood vessels in the child's eye. The next day, day care workers noted fresh bruising and scratches on her cheek. They found more on the baby's back while changing her clothes March 23.

Each wound was documented, and workers reported their findings to Hennepin County Child Protection. The mother could not provide an explanation for the injuries, telling investigators that the baby had suffered from a cold but was otherwise healthy, according to court records.

On March 24, the mother left the baby alone with McMorris instead of bringing her to day care. She didn't notice anything abnormal about her behavior the previous evening or before she left for work, she later told authorities.

When responders arrived, the infant was lying on the ground. McMorris said she had stopped breathing and began vomiting, but he provided no explanation for what caused the distress. He gave inconsistent accounts of when the baby became unresponsive and what she was wearing, police said.

McMorris has a warrant out for his arrest.

Liz Sawyer • 612-673-4648