The parents of six children left at home were at a nightclub early Sunday morning when a fire broke out at their Antioch apartment, killing an infant and injuring the others, police say.

Police say the children's mothers — two women, ages 23 and 25, who were friends — had been out at a club together when the unit caught fire sometime after 2 a.m. at Hickory Lake Apartments on Apache Trail.

Metro Nashville Police spokesman Don Aaron said officers have been unable to substantiate a claim by the mothers that a babysitter was present with the children, the oldest of whom was 6. Officers did not locate a babysitter at the scene.

"There are a number of unanswered questions at this moment," Aaron said.

NASHVILLE FIRE:What we know about the Antioch apartment fire that killed 8-month-old girl

Jream Jenkins, an 8-month-old girl who lived in the apartment, died in the fire. The infant's 23-month-old brother is in critical condition after suffering life-threatening injuries.

The four other children, ages 6, 4, 2 and 1, are from Linden.

All of the surviving children remained at Monroe Carell Jr. Children's Hospital as of Sunday afternoon.

The fire marshal's office, Metro Nashville Police Department's youth services division, South Precinct investigation division and state Department of Children's Services all are investigating.

Nashville Fire Department spokesman Joseph Pleasant said arson detectives were involved in the investigation.

"The circumstances of the fire and the cause of the fire remain under investigation by the fire marshal's office," Aaron said.

Child came running out of apartment screaming as fire broke out

The initial call about the fire came from two passersby who saw the blaze and called 911. They witnessed the 6-year-old child running out of the apartment building screaming, Aaron said.

When firefighters arrived, they encountered flames and heavy smoke coming from one of the units. Dispatchers informed firefighters that several people were trapped inside, while one person was rescued from a third-floor balcony, Pleasant said.

Bystanders told firefighters that several children were inside the burning building, prompting members of the department to search for the children and remove them from the apartment.

The infant was pronounced dead at the scene.

Pleasant said the fire was contained to one apartment, while smoke damage affected other units nearby.

The American Red Cross responded to the scene to provide temporary housing and other resources to impacted residents.

Reach Natalie Allison at nallison@tennessean.com. Follow her on Twitter at @natalie_allison.