jamyra gallmon , 21 , was arrested on wednesday on first-degree murder charges related to the february 9 death of david messerschmitt .
the 30-year-old lawyer told his wife he would be home that evening but never showed ; he was found stabbed to death the next day at a hotel .
items recovered from the room included a computer , lubricant , condoms , cell phone and enema kit .
police sources told nbc washington that gallmon was at the hotel that evening for a ` sexual encounter '
gallmon 's mother spoke with nbc and said her daughter had never been in trouble before and was considering joining the military .