BOULDER, Colo. -- A 19-year-old freshman may have limited time left at the University of Colorado after being arrested for allegedly tossing a mirror from his 12th floor dorm room over the weekend.

Rolf William Johnson, 19, was arrested Saturday and faces charges of second-degree assault, third-degree assault and reckless endangerment.

Joshua Moran, 20, was standing near Stearns West residence hall at about 2:30 a.m. Friday when a 3-foot-long dressing mirror smacked him on the back of the head.

"(It was) Pretty bad. Officers arrived and they found a fair amount of blood," a CU police spokesman said.

"The glass was three-quarters to an inch thick," Moran's father, Richard Haly, told the Daily Camera. "That's pretty significant."

CU police Cmdr. Brad Wiesley said glass shards were imbedded in the back of Moran's scalp, and the incident could easily have been fatal.

Moran was released from the hospital later that day but he has several appointments to make sure he does not have swelling in the head.

Madison Mangines was also hit by the glass. She was cut on her right foot.

Her mother, Lianne Mangines told 7NEWS, "I can't imagine this person would do this intentionally. But it certainly wasn't a good decision."

Her daughter was well enough to go on a spring break trip out of the country this week.

The mirror had traveled 43 feet away from the base of the tower.

Johnson, told CU police he was "frustrated, upset, angry and just wanted to break something."

Police think he ripped a standard, wall-mounted mirror measuring three feet in length and one foot across out of his dorm room and tossed it out the window.

"He said that he expected it to just drop onto the roof below his room...but that it fluttered and moved with the wind," the arrest affidavit stated.

"Not a lot of thought went into the act before it happened. Because, I think a lot of people look back and say what was he thinking?" said Wiesley.

Johnson tells police his girlfriend in his hometown of Villanova, Penn., had become a relationship problem and he feared for her safety.

His actions concerned police enough that they checked "yes" on a form indicating whether an inmate has caused the officer to believe the inmate may be suicidal.

Johnson posted a $ 5,000 bond and is out of the Boulder County jail.

"Easily. I mean, I can see a three-foot by one-foot sheet of glass falling from the sky, causing all kinds of fatal injuries," Wiesley said.

Student affairs officials said they could not comment on Johnson's case, citing federal privacy laws, but did say the matter would likely be referred for some sort of disciplinary action.

Wiesley said, based on previous assault cases, expulsion would be one of the options available to CU administrators.