SEVERNA PARK, Md. -- A 4-year-old girl and her grandfather drowned in a backyard pool Thursday afternoon in Maryland.

CBS Baltimore reports the drowning happened in Severna Park. The two were swimming in a neighbor's pool after getting permission to use it.

The Anne Arundel County Fire Department said there were other children there at the time of the drownings.

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The 4-year-old reportedly jumped into the deep end of the pool, but she did not know how to swim.

Other children noticed she was at the bottom of the pool and told her grandfather, who also didn't know how to swim. He then jumped in to try and save her.

The other children ran across the street to get other family members, who immediately call 911 after seeing the two at the bottom of the pool.

"They alerted the male that was watching them. He jumped into the pool but unfortunately did not know how to swim and began to get into some distress himself," said Lt. Jen McKee of the Anne Arundel County Fire Department. "And the fire department immediately pulled both of the victims out of the pool. They aggressively tried to resuscitate both of them, but unfortunately, by the time they got to the hospital, and the hospital tried to resuscitate them, they weren't successful."

The two were taken to a hospital after being removed from the pool, but were later pronounced dead. Police have not released the names of the victims. They want to make sure family members are notified first.

The police department said homicide detectives were on scene, but the investigation is now closed because it's clear this was an accident.