The family of a Potomac teen who, along with her boyfriend, killed a Gaithersburg man last year, hopes that she serves her sentence in a state mental health hospital instead of prison.

"That's our hope; that she gets the help she needs," said Emily Geller's father, Donald Geller, who adopted her when she was 2 days old. "Clearly she has some issues to deal with."

Emily Geller, 18, of Potomac pleaded guilty to first-degree murder to avoid a sentence of life imprisonment July 28, said her attorney, Barbara Graham. Geller and her boyfriend, Artie Ellis, 16, of Potomac killed Ali Reza Zare, 57, of Gaithersburg in May 2009.

Zare's family could not be reached.

In the plea deal, Geller likely will serve up to 25 years in prison and has a recommendation for screening in hopes of spending her sentence at the Patuxent Institution — a mental health correction facility in Jessup.

"She was looking at spending her entire life without parole if convicted by a jury," Graham said. "This way she has a chance at rehabilitation of some sort."

During the July 28 hearing, Geller said she had been diagnosed with and is being treated for bipolar disorder, depression and attention deficit hyperactive disorder.

Geller's biological mother reportedly used cocaine while pregnant, Graham said.

Ellis pleaded guilty to first-degree murder in May, according to court documents. He and Geller were both charged with first-degree murder last year.

Geller, in her deal, is acknowledging her part in the May 10, 2009, killing of Zare where she reportedly led him into the woods near Bells Mill Elementary School with the promise of sex in order to rob him.

Zare was found dead by a jogger early that morning, later determined to be from a blunt-force wound to the head caused when he was struck by a shovel.

Prosecutors say both Ellis and Geller played a role in the murder.

"She admitted it was her idea to play like I was going to have sex with him and lead him down the nearby path where Mr. Ellis would be waiting," Carol Crawford, the Assistant State's Attorney prosecuting the case, said in a hearing July 28.

Detectives connected Geller to the murder after finding her fingerprints in Zare's car, a blue Subaru, found abandoned on Bradley Boulevard near Seven Locks Elementary, according to police charging documents.

Video evidence showed a young man and woman, whose descriptions are consistent with Geller and Ellis, trying to use Zare's credit card at an ATM machine shortly after his death.

A search warrant executed for Geller's home in Potomac — a half mile from where Zare's body was found — on May 18 uncovered the shovel used in the crime. Forensic evidence on the tool was inconclusive, Crawford said.

Geller met Zare while walking to the White Flint metro station earlier in May 2009, Crawford said. Zare offered her a ride and later money to have sex with him, Crawford said.

He reportedly paid her $60 that day, she said.

Ellis and Geller were dating at the time of the incident and his influence on her played a significant part in the events leading up to the crime, Graham said.

"I think there's a lot of information about this case that will never come out," she said. "[Geller] has a lot of mental health issues and, honestly, she was in love with a man with a history of violence."

In his guilty plea, Ellis agreed to testify against Geller, claiming she planned the robbery.

"She knew the victim, she had a previous relationship with him and was the one who selected him for the robbery," said Ellis' attorney, Rene Sandler. "The case overwhelming supported that it was Ms. Geller who planned it."

Geller also pleaded guilty to automotive theft for stealing Zare's car. The agreement would allow her to serve the maximum five year sentence concurrent with her life sentence for murder.

Geller is scheduled to be sentenced in October. Ellis is scheduled to be sentenced in September.