MIAMI -

Police arrested a babysitter who left two children alone at their home in Cutler Bay before a fire started there.

Police arrested Andrew Sepulveda Wednesday. He was charged with two counts of child neglect with great bodily harm.

The house fire happened at 10241 Martinique Drive about 1:30 p.m. Wednesday.

The children, a 6-year-old girl and 4-year-old boy, were airlifted to Jackson Memorial Hospital in serious condition, authorities say. Both suffered smoke inhalation.

According to the arrest affidavit, Sepulveda, 31, left the children alone at the home and locked the doors, which prevented them from exiting when the fire started.

Miami-Dade police detective Roy Rutland said Sepulveda went to pick up groceries with his girlfriend and his own children.

"I don't think you need to be a detective to look at this scene behind me to realize we have two small children left alone and realize that's a concern," said Rutland.

"There were three that were with them in the car and two that stayed home because they didn't want to go," said neighbor Scott Dundry.

Police believe the two children somehow sparked the fire, although it's unclear how it started.

The children were both listed in critical condition Thursday. The girl was breathing on her own, said doctors, but the boy using with a ventilator.

A judge ordered Sepulveda be held on $25,000 bond.

Sepulveda was fined for petit theft in 2008 and convicted of driving with his license suspended in 2006, according to police records.