Jury finds mother guilty of murder in girl's drug death A South Shore mother was found guilty yesterday of second-degree murder in the death of her 4-year-old daughter, Rebecca, who went to sleep one night after being given toxic levels of psychotropic drugs and never woke up. Carolyn Riley, 35, showed no visible emotion when the 12-member jury returned the verdict after 19 hours of deliberations in Plymouth Superior Court. Riley, her upper chest displaying a 'Rebecca 12-06-06' tattoo that reflected her daughter's date of death, was handcuffed as soon as the word guilty was uttered by the jury forewoman. Before sentencing, Judge Charles Hely permitted the reading of a letter from Ashley Davidson, 17, Riley's first biological daughter, who as a toddler was removed from her mother's care, placed in a foster home, and eventually adopted. The teenager condemned her mother for the cruel fate she delivered Rebecca, as well as the tormenting memories left for her and Rebecca's two other siblings, ages 14 and 9, now both in foster homes. 'When I think that you are my biological mother, I sometimes wonder if it is in my blood. Will I grow up to be a mother like you?' said the letter, read by her adoptive father, Bob Davidson. Riley, who has an additional tattoo on her arm with the name Ashley, listened and stared at the floor. The judge sentenced her to life imprisonment, with the possibility of parole after 15 years, the mandatory punishment for a second-degree murder conviction. It was one of the lesser offenses that the jury of eight women and four men was allowed to consider in this first-degree murder case. As officers led Riley out of the courtroom, she looked at her mother, Valerie Berio, a constant presence in the 3?-week trial who was sobbing among the spectators. Riley quietly wept as she was taken our to be transported to MCI-Framingham. While Plymouth District Attorney Timothy J. Cruz praised the verdict as 'a small measure of justice for Rebecca,' the mother's defense lawyer, Michael Bourbeau, said the decision, which he plans to appeal, reflects the jury's judgment of 'what kind of a mother she was,' as opposed to the evidence in the case. He had argued to jurors that medical evidence showed that Rebecca died of fast-acting pneumonia, not drugs, and that the mother gave medications based on the sometimes-flexible instructions of her child's psychiatrist. Riley's husband - Michael Riley, 37 - will be tried separately on the same charges, and his case is scheduled to go to trial next month unless yesterday's result leads to a plea bargain. Rebecca's case attracted national attention to the expanding use and potential abuse of giving psychotropic drugs to very young children. When Rebecca died, she and her two older siblings, Gerard and Kaitlynne Riley, were each on three potent psychiatric medications for bipolar and hyperactivity disorders. Each of them went on the drugs at age 2. Prosecutors say Carolyn and Michael Riley, Weymouth High School graduates who had been living briefly in Hull when Rebecca died, deliberately sought the psychiatric drugs for their three children to scam their local Social Security office into approving disability benefits. But behind the twists of the case is the all-too-familiar tale of a deeply troubled, financially strapped couple whose capacity to harm their children became catastrophically evident - to their many doctors, psychiatrists, teachers, and social workers - only when it was too late. The prosecutors, Frank J. Middleton Jr. and Heather Bradley, depicted Carolyn Riley as an unusual form of child abuser, a woman who used three sedating medications, including Depakote, Seroquel, and clonidine, to control her energetic toddlers and induce sleep. Remarkably, prosecutors said, Carolyn Riley managed to obtain the drugs routinely through prescriptions from Dr. Kayoko Kifuji, a Tufts Medical Center psychiatrist who faces a medical malpractice lawsuit in the death and agreed to testify only after being granted immunity from prosecution. On the night Rebecca received her fatal overdose, her father, who had been prone to violent outbursts, became irate about the child's pleas to be with her mother. Rebecca had been battling a respiratory illness for days, and that night, according to housemates, Rebecca kept trying to enter her parents' bedroom, moaning, 'Mommy, Mommy.' Prosecutors said that the mother, whom they portrayed as routinely putting her husband's needs above her children's, went to the pill dispensers in their Hull home. That night, the state said, Carolyn Riley gave the coughing and feverish child as much as twice the girl's daily dosages of clonidine at once, the equivalent of seven tablets of .1 milligram each. Rebecca's lifeless body, clad only in a pull-up diaper with a teddy bear beneath her head, was discovered by her mother around 6 a.m. on Dec. 13, 2006, next to her parents' bed. Her defense lawyers, however, portrayed Carolyn Riley as an overwhelmed mother deserving of sympathy, a former foster child who was doing her best to raise a family in which the adults and children all had mental health problems. If the mother had some lapses, her lawyers said, they had to be viewed in light of the difficult choices of a woman struggling with poverty and a domineering husband. In the year before Rebecca died, Michael Riley saw the children sporadically. He was barred from living with the family in a Weymouth housing development because he had been charged with trying to sexually assault and show pornographic pictures to Ashley during one of her visits with the family. The father, who was convicted of only the pornography charge and served a 2?-year prison term that ended this year, remains behind bars awaiting his trial in the death of Rebecca. The attachment of Carolyn Riley to her husband was a recurring theme in the lengthy trial. As the mother waited over three days for a verdict, sitting on a bench reading a romance novel and playing games on her cellphone, she responded readily to reporters' questions. When asked about the prosecutor's argument that she and her husband wanted only to maximize their disability benefits, the mother, who speaks with a soft, girlish voice, disputed that point. She said that Social Security awards more money in total to a couple who file as unmarried singles. But, she said that she and Michael, together for more than 15 years, chose to remain true to their status as a wedded couple. 'We would have gotten more money if we weren't married,' she said. Patricia Wen can be reached at wen@globe.com. 