HoCo Teen Pleads Guilty To Killing Father

ELLICOTT CITY, Md. (WJZ) -- A teenage girl pleads guilty Tuesday to her role in a plot to have her boyfriend murder her father in Howard County two years ago.

Derek Valcourt has reaction from the girl's mother.

The girl's parents were divorced and her mother blames mental illness, but in court prosecutors say the girl's diary showed she hated her father.

58-year-old real estate executive Dennis Lane made a name for himself as popular Howard County blogger who co-hosted a podcast.

But Lane's May of 2013 murder inside his Ellicott City home stunned the community.

When police arrested his then 14-year-old daughter Morgan Lane Arnold and her 19-year-old boyfriend Jason Bulmer, saying the two plotted for weeks to kill her father.

Bulmer's now already serving 30 years in prison after confessing to sneaking inside the family home to stab Lane as he slept--telling officers, "I'm the one who did it, she (Arnold) told me to."

Text messages confirmed Arnold asked Bulmer to stab her father in the throat 10 times.

"My daughter is mentally ill," said Cindi Arnold.

Cindi Arnold says her daughter doesn't fully understand the consequences of her actions.

"She at a young age was denied a lot of mental health support that she needed and this didn't happen in a vacuum.  This was the result of things that were going on prior in her life and the stresses that she was going through," she said.

Because of her long history of mental illness Arnold's attorneys had plan to argue that she was not criminally responsible by reason of insanity. But because of the calculating nature of this crime they acknowledge that would have been hard to prove.

Howard County prosecutors will ask for a sentence of life in prison with parole.

The defense will ask Arnold be placed in the youth Offenders program at Patuxent Institute, her mother says Morgan needs mental health support.

"She's just a child and developmentally she's very young and she does deserve a chance at a life," said Cindi Arnold.

Sentencing is set for August 28th.

Defense attorneys had asked that the case be heard in juvenile court but a judge refused and ordered Morgan Arnold be tried as an adult.