A woman was charged in the death of her stepsister and another toddler after they drowned as she slept off a night of drinking, police said.

Brittany N. Steward, 19, was arrested Tuesday on charges including involuntary manslaughter. A preliminary hearing was tentatively scheduled for Monday.

"OK im finally done drinking and im rocked lol," she text-messaged a friend, using shorthand for "laughing out loud." The message was sent between 7 a.m. and 8 a.m. last Wednesday, police said. Hours later, the children were dead.

Steward returned home from a party between 6:30 a.m. and 7 a.m. to baby-sit her 20-month-old stepsister Jenna Walker and a family friend, 2-year-old Maggie Kovski, police said.

She awoke later in the morning to find the garage door open, police said. Steward found the girls' bodies floating in a pond about 150 yards from the house. She tried performing CPR and called 911, police said.

A man who answered the phone at Steward's home in Waterford, just south of Erie in northwest Pennsylvania, declined to comment.

Steward probably had five or six beers, according to a friend who left the party at about 1:40 a.m. and received Steward's text message.

Authorities would not say whether Steward's blood-alcohol level had been tested.

Steward was charged with two counts each of involuntary manslaughter, endangering the welfare of a child and recklessly endangering another person. She was being held in the Erie County jail on $50,000 bond.

It was not immediately clear if she had an attorney.

A relative of Maggie's said the Kovski family was not commenting.