Meg was married to Paul Collins, a captain for the U.S. Armed Forces and a decorated war hero. The two had a daughter named Sophia together and maintained a steady and happy family life, although Meg was often worried whenever Paul would be sent out on tours. Two weeks prior to Public Enemy, Paul returned back to the U.S. from his fourth tour in Iraq.
On February 7, 2010, Meg attends an early Mass service with Paul and Sophia, the latter of whom she becomes tense with when she continues playing with her doll. Eventually, during prayer, Meg becomes agitated and tries taking Sophia's doll away, causing the both of them to argue. With their attention away from Paul, as well as everyone else's, this allows Connor O'Brien to quickly slash Paul's throat and flee, intentionally discarding his weapon right afterward. Meg, Sophia, and the other Mass attendants watch in horror as Father Kendellen (who is on familiar terms with the family) tries to tend Paul and yells for someone to call 911. Unfortunately, Paul quickly dies from his neck wound. Due to the connection in M.O. to two previous murders, the BAU is called in by the local police to investigate. During that time, all media outlets, spurred by the murder of a high-ranking soldier serving in the Iraq War, swarmed the Collins home in hopes of getting interviews from her, resulting in Meg shutting herself and Sophia inside. Because Meg got the best look at Connor during Paul's murder, JJ and Morgan are sent by Hotch to interview her.
During the interview, Meg, almost about to suffer from an emotional breakdown, tells JJ and Morgan that she received a call from the military, asking if she wanted Paul to be buried at Arlington, Virginia. Then, she recounts what she saw at the church, but her testimony doesn't prove to be enough for a proper description of the unsub. When Sophia tells JJ that Connor actually shook her hand right before communion, this enrages Meg. Later on, as the investigation progresses, JJ stays behind with Meg and Sophia to ward off the media presence outside of the house. Eventually, she comes to befriend the both of them. After more victims are killed by Connor, the BAU decide to hold a press conference that would cause the public to congregate around one of the crime scenes without any fear, and intended to have Meg speak during the conference. However, when JJ tells her this, Meg refuses, not wanting to be targeted by Connor as well. Later on, Connor kills a mother in front of her baby, which finally causes Meg to reconsider and hold the press conference, causing a candlelight vigil to congregate around the church that Paul was killed in. Her speech causes Connor to angrily go to the vigil with the intention of killing an attendant, only to be apprehended by the BAU, who profiled that he would respond in such a way.