Story highlights Source: Bobbi Kristina Brown has injuries that still need to be explained

The 21-year-old has been in a medically induced coma for a week

Atlanta (CNN) Investigators are focusing on Bobbi Kristina Brown's boyfriend, Nick Gordon, as they try to determine how she ended up facedown in a tub of water, a source with knowledge of the case told CNN.

In another development, a source close to her family told CNN that she has injuries that still need to be explained. The nature of those injuries was not disclosed.

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The daughter of musical superstar Whitney Houston, Bobbi Kristina was found facedown in a bathtub full of water in her Atlanta area home on January 31. The 21-year-old was "unresponsive, meaning not breathing, no heartbeat," a Roswell police spokeswoman said at the time.

Doctors have placed her in a medically induced coma, a source close to the family said soon after she was hospitalized. The status of her brain function won't be known until sedatives are reduced, the source said.

A week after she was rushed to the hospital, details of her condition are scarce. Sources close to the family say she opened her eyes briefly on Monday and also suffered seizures that same day. It was not immediately clear what medical significance these reported events have in Brown's case.