Indianapolis police revealed Saturday that homicide detectives are leading the investigation into the disappearance of an infant girl reported missing two weeks after she was last seen alive with her mother’s boyfriend.

The Indiana police fear the worst because they said 8-month-old Amiah Robertson hasn’t been seen since March 9. They also found "items" of hers along a river bank Wednesday after getting a tip.

"I think that we all hope for the best always, but I think that we can't ignore the reality of the situation," Lt. Bruce Smith said. "Amiah cannot take care of herself. And absent somebody else who is currently taking care of her that hasn't come forward, we are very concerned about what happened to her."

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Police named 20-year-old Robert Lyons as the person who was with Amiah when she was last seen. He is the boyfriend of the girl’s 19-year-old mother, Amber Robertson.

On March 9 Lyons left the babysitter’s with Amiah and then showed up hours later at Robertson’s without her, police said. The next day he allegedly taunted Robertson about Amiah's whereabouts.

“He is certainly a suspect in her disappearance,” Smith said.

Police said Lyons wasn’t being sought at this time. They said they spoke to him after family reported Amiah missing on March 16.

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Det. Jeannie Burket said Lyons told her where Amiah “should be alive and okay.”

“Some places she was said to be by Robert do not exist,” she said.

Robertson has been cooperative, police said.

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Burkert asked for anyone who may have seen Lyons on March 9 to come forward.