INDIO, Calif. -

Closing arguments are expected to get underway today in the case of a man accused of killing his two-month old daughter in Desert Hot Springs.

Jason Michael Hann, 38, is charged with one count of murder, with a special circumstance allegation of having a previous murder conviction, and one count of assault on a child causing great bodily injury. 

He could face the death penalty if convicted.

Krissy Lynn Werntz, the baby's 34-year-old mother and Hann's then-girlfriend, is also charged with murder and will be tried separately.

Deputy District Attorney Lisa DiMaria said in her opening statement earlier this month that Hann fatally struck infant daughter Montana with a closed fist in February 2001, inflicting severe skull fractures.

Montana's lifeless body was placed in a Tupperware container, which was then put in the trash bag and kept inside a trailer for a year at an storage unit in Arkansas, DiMaria said.

When Hann and Werntz stopped making payments, the trailer was auctioned off to an Arkansas man, who discovered the bag in February 2002, DiMaria said. 

The man inadvertently placed the bag inside a dumpster and saw what looked like a skeletal hand, prompting him to call police, the prosecutor said.

An all-points bulletin was sent to law enforcement agencies around the country, and Hann and Werntz were arrested in April 2002 at a motel in Portland, Maine.

The day after they were arrested, police found the remains of another of their children, a boy less than 2 months old, in a storage unit in Arizona. 

That baby, named Jason, had been killed in July 1999 in Vermont.

His remains were placed in a plastic container and kept by the couple for about a year before they rented the Arizona storage unit.

In February 2006 in Vermont, Hann entered a no-contest plea to second-degree murder in the baby's death and was sentenced to 27 to 30 years in prison.

Werntz wasn't charged in that case.

Authorities investigating the couple determined that their third child, a boy about a month old, had  skull and rib fractures, DiMaria told jurors. That boy was later adopted and renamed.

While being questioned, Hann told police that the couple's daughter Montana had died in Desert Hot Springs, according to the Riverside County District Attorney's Office.

Defense attorney Brenda Miller told jurors in her opening statement that her client has suffered from bipolar disorder since early childhood. He endured mental health problems such as anxiety, depression, agitation and has harbored thoughts of suicide ``all his life,'' Miller said.

She said Montana's cries made Hann reach an extreme peak in his severe mood swings.

Montana was born in Arizona on Dec. 1, 2000, and the family moved to California about a month later.

Werntz told Riverside County sheriff's Investigator Gary LeClair that on Feb. 10, 2001, she went to work and Hann stayed at their motor home with Montana. When Werntz returned home, she picked up Montana, but the baby was dead, LeClair wrote in a declaration in support of an arrest warrant.

Hann was in prison for his son Jason's death when officials in Vermont agreed to extradite him to California to stand trial for Montana's death.

He and Werntz were indicted by a grand jury in September 2009, according to court records.