A woman who wrote on Facebook that "Mommy loves you, my angel" after her 3-year-old daughter was found dead in a ravine in a neighboring suburb was convicted Friday of killing her by a jury that deliberated for four days.

Adrienne Williams, 37, was found guilty of third-degree murder, evidence tampering and abuse of a corpse in the death of Adrionna Williams. The murder conviction alone carries a maximum 20- to 40-year sentence.

Prosecutors contend the Wilkinsburg woman asphyxiated Adrionna before leaving the girl's body in a wooded area of Swissvale in June 2015. Williams' attorney had argued that the failure to pinpoint exactly where and how the girl was killed meant Williams shouldn't be convicted.

Williams had said she left the girl at her grandmother's house and went to work. But surveillance video and cellphone records showing Williams drove to and from the area where Adrionna's body was found proved she was involved in the death, prosecutors said.

The jury seemed to struggle with the circumstantial nature of the case, asking the judge on Wednesday to define again for them the legal concepts of circumstantial evidence, reasonable doubt and premeditation.

Prosecutors had sought a conviction of first-degree murder, characterized as a malicious killing with premeditation that carries a mandatory sentence of life in prison. The third-degree verdict means the jury did not find that the crime was premeditated.

The jury had told the judge Thursday that it was nearing an impasse "due to arguments being made without factual support" by at least one juror. It wasn't immediately clear after the verdict what prompted those concerns.

Adrionna's body was discovered by a dog walker about 40 minutes after her family reported her missing June 14.

The morning after Adrionna's body was found, Williams mourned her daughter on Facebook, writing, "Give me my angel back, please" and "Mommy loves you, my angel." The girl's death also prompted a march several days later as community leaders decried the crime and asked for the public's help.

But according to charges later filed by police, investigators had found items in Williams' car that, coupled with the cellphone and surveillance video, strongly suggested she was the killer.

Among other things, police found several colored paper clips near the girl's body similar to clips later found in Williams' car. Also found in the car were small splotches of mud and Williams' uniform shirt, which was stained with the girl's DNA and watermelon — a treat the girl was eating just before she was last seen.

Police believe Williams left for work only to have the girl follow her out onto the porch. Nobody saw what happened after that, though the girl's grandmother, aunt and two cousins at the duplex all assumed Williams left for work, police said.

Family members recalled that Williams had seemed to be annoyed that her daughter needed help cleaning herself after using the bathroom shortly before Williams was supposed to leave for work.