A mistrial was declared Tuesday in the case of a Tucson woman accused of murdering her newborn son and tossing him in the trash.

A Pima County jury deliberated 12 hours over three days before announcing they were deadlocked on the first-degree murder and child-abuse counts facing Denise Pesqueira. The forewoman also told Judge Clark Munger the jury couldn't reach a unanimous decision on the less-serious charges of second-degree murder and manslaughter.

Deputy Pima County Attorney Anita Simons is expected to announce July 10 if her office intends to try Pesqueira again.

Pesqueira, 22, was arrested in March 2010 after a friend, Mark Lopez, told police she'd told him she'd given birth and put the baby in the trash. She later repeated her story as police secretly listened. Authorities suspect the baby was born in August 2009, but because of the lapse of time between Pesqueira's confession and the birth, no body was ever found.

Pesqueira told Lopez she gave birth to a son in her bathroom and her mother knocked on the door after she heard the baby cry. She placed the baby in towels and blankets and threw the baby into a trash bin.

During closing arguments Friday, Simons told jurors that if the baby had died of natural causes, Pesqueira would simply have said so. In addition, Simons pointed out that Pesqueira repeatedly refused to answer Lopez when he asked her if she had suffocated the baby.

Simons asked the jurors why Pesqueira didn't take her dead son to the hospital since she told Lopez she believed Arizona's Safe Haven Law allows parents to leave stillborn babies at hospitals, Simons said.

The prosecutor urged the jurors to hold Pesqueira responsible for her actions.

"This wasn't garbage, folks. These weren't the remains of her child, this was a living, breathing child," Simons said.

Without the child's body, the state has no direct evidence he was murdered, Assistant Pima County Public Defender Sheena Chawla told jurors. The child could have cried and then died on his own, she said.

Chawla reminded jurors they heard evidence that back in 2009, Pesqueira suffered from an uncontrolled thyroid condition that often results in premature or stillbirths and genetic defects. Pesqueira's mother also had difficulties during her pregnancies, Chawla said.

Just because Pesqueira told people she was considering having an abortion because she feared her parents' reaction to the pregnancy doesn't mean she killed the baby, Chawla said.

Pesqueira is guilty of using bad judgment for having an unattended home delivery, but she's not guilty of murder, Chawla said.

If tried again and convicted, Pesqueira is facing life in prison with release possible after 35 years, plus a consecutive sentence of 10 to 24 years.

She rejected a plea agreement that would have guaranteed her seven to 21 years in prison for manslaughter.

Contact reporter Kim Smith at 573-4241 or kimsmith@azstarnet.com On StarNet: Follow the news and events at Pima County's courthouses in Kim Smith's blog, At the Courthouse, at azstarnet.com/courthouse