Police believe the 14-year-old daughter of Howard County blogger Dennis Lane conspired with her 19-year-old boyfriend to kill her father, who was stabbed to death inside his Ellicott City home Friday morning. (Jon Sham/Baltimore Sun video)

As 2012 drew to a close, a posting on 14-year-old Morgan Lane Arnold's Facebook page warned of the apocalypse.

"The world shalt end this year!!!" reads a post on the page, which multiple friends confirmed belonged to Arnold. Her father, Dennis Lane, weighed in a few minutes later: "We'll find out next week if you're right..."

Her next post: "Yay."

The world didn't end, but their lives would change dramatically a few months later. Lane was found dead in his Ellicott City home early Friday, and Arnold and her 19-year-old boyfriend, Jason Anthony Bulmer, have been accused by police in his killing.

The two teenagers were charged late Friday and early Saturday with plotting the murder. Police said they are still investigating and don't know of a motive, leaving many unanswered questions about the relationships between the daughter, father and boyfriend.

Friends describe a caring family as well as a burgeoning affection between Arnold and Bulmer. But even as the father frequently blogged about happy times spent with his daughter, and her Facebook page was filled with loving posts about her boyfriend, one close friend said Lane had been privately upset over the past year.

"I've actually been in a funk for about a year now," Lane wrote late last year to longtime friend Jessie Newburn, who shared the Facebook exchange with The Baltimore Sun. "Many things have contributed but I realize the path out of this is within my control … I hope it isn't too noticeable."

A woman who answered the door Saturday at the Catonsville rowhouse of Cindi Arnold, Morgan Arnold's mother, declined to comment. Members of Lane's and Bulmer's families also declined to comment. And a man who answered the door at Lane's home declined to comment.

Arnold and Bulmer have been charged as adults with conspiracy and murder counts, according to online court records. They are being held without bail at the Howard County Detention Center.

Charging documents in the case were not available Saturday, and Howard County State's Attorney Dario J. Broccolino said he had been briefed on the case but declined to comment.

Police said Friday that the pair had been discussing the murder through "electronic communication" for two months and planned to run away together after committing the crime. Police declined to elaborate on the kinds of electronic messages they are investigating.

Early Friday morning, police said, Arnold left the basement sliding glass door unlocked. Bulmer stabbed Lane multiple times after Arnold urged him on, police said.

Another adult at the home called the police, and officers arrived to find the teenagers sitting in a bedroom at the Ellicott City home — Bulmer's hands and clothes were bloody, according to police.

Lane and Cindi Arnold shared custody of Morgan, and court records show they fought a legal battle with one another between 2008 and 2009.

Newburn said Lane seemed exhausted by the dispute over custody of his daughter and appeared depressed when they met one time last year.

Then over the Christmas holiday, Newburn corresponded with Lane by Facebook and asked him whether everything was OK. Lane blamed part of his problems on slacking off on his exercise routine, but Newburn said in an interview that she detected other issues, too.

"He was paying all this money and having legal fights with Cindi and was really just trying to advocate what was best for Morgan and that she had a good stable home and was going to school," she said. "He was exhausted. … He was just tired of fighting."

Meanwhile, Lane, a commercial real estate agent, continued to build his public persona as a prominent blogger and podcaster. His death sent shock through the blogging online community in Howard County that many credited Lane with shepherding into existence.

David Bittner, the co-founder of the blog "HoCoMoJo" and producer of Lane's podcast, said Lane "wasn't someone who was willing to stand by on the sidelines."

"He was truly invested in making this community a better place. If that can be his legacy, he would be happy to have that," Bittner added.