A Prince William County jury yesterday convicted a Dumfries woman whose 6-month-old daughter drowned in a bathtub while she lay asleep on her couch after snorting powerful prescription drugs.

After deliberating two hours, the jury found Alison Nicole Spivey, 25, guilty of felony child abuse and involuntary manslaughter, both of which carry maximum sentences of 10 years. The sentencing phase of the trial will begin today.

As the jury read the verdict, Spivey maintained the calm expression she has had throughout most of the two-day trial.

Assistant Commonwealth's Attorney Sandra R. Sylvester, who for 18 years has tried similar cases, said Spivey's level of intoxication proved the most compelling evidence in the case.

"There was just no way around that evidence," Sylvester said. "Sadly, this case was not out of the norm of child neglect cases in this county. That's probably the saddest part of all."

About 8:30 a.m. Aug. 27, Joseph Patrick Mott, the father of 6-month-old Josephine Emma Mott and Patrick Mott, 3, dropped the children off at Spivey's trailer. About an hour later, after snorting the potent pain reliever OxyContin with her roommate Stephen R. Wendel, 35, Spivey placed Josie in a playpen and went to sleep.

While she slept, Wendel drew baths for Patrick and Josie, placing the children in separate tubs. Wendel then passed out on the floor of the master bedroom. Whether Spivey ordered Wendel to give the kids a bath or knew of his actions was disputed.

Spivey awoke about 12:30 p.m. to Patrick trying to rouse her. When she entered the hallway, the floors were glistening with water, the walls were warped with moisture, and Josie was lying face down in a tub filled to the brim.

During the trial and in closing statements, prosecutors emphasized Spivey's inebriation as a sign of parental negligence. They said she had delegated responsibility to Wendel, whom Spivey knew to be on drugs.

"That's what parents do. They make us feel safe. They make us feel secure," Sylvester said during closing arguments. Spivey "wasn't a parent that day. She put her own needs above her children."

The defense tried to raise reasonable doubt, citing conflicting police reports about what Spivey knew or didn't know about Wendel's actions. Denise Tassi, Spivey's attorney, also emphasized Spivey's responsible behavior by reiterating how she had placed Josie in a secure playpen.

Wendel testified yesterday that he and Spivey had illegally snorted OxyContin that morning. A toxicologist said Spivey's blood had abnormally high levels of the opiate found in OxyContin -- levels that in some cases are fatal unless an individual has developed a tolerance. Wendel's levels were lower, but testimony revealed that he was in and out of consciousness and had only a vague recollection of the incidents of that day.

In March, Wendel entered Alford pleas to involuntary manslaughter and child abuse. The pleas were not an admission of guilt but an understanding that there was enough evidence for a conviction. He will be sentenced July 21.

Dumfries police officer Debra Cochran said she was told on the scene that Spivey and Wendel were leaving for the beach that day. Wendel wanted to do Spivey a favor and clean the house and bathe the children, Cochran said.

"I loved [the children] very much," Wendel said yesterday.

A medical examiner said that Josie, before her death, was in good health but that forensic specialists also found dirt in the creases of her neck, often an indication of poor child care.

Alison Spivey was found guilty of felony child abuse and involuntary manslaughter.