A former substitute teacher in Maryland is facing attempted murder charges after authorities say she stabbed her teenage son in what investigators describe as a planned murder-suicide inside their home. Prosecutors allege that Selina Mui of Manchester attacked the boy in his bedroom, leaving him with multiple serious wounds before he managed to escape and survive.
The case has stunned Carroll County, where Mui previously worked in classrooms, and raised fresh questions about how quickly a family crisis can escalate into life-threatening violence. Court documents outline a prolonged struggle between mother and son, with officials now piecing together how a parent entrusted with students’ safety could be accused of trying to kill her own child.
The Alleged Attack Inside a Manchester Home
Investigators say the violence unfolded inside the family’s Manchester residence, where 46-year-old substitute teacher and mother Selina Mui of allegedly entered her teenage son’s bedroom armed with a knife. Charging documents describe Mui waking the boy and then repeatedly stabbing him, focusing on his back and neck as he tried to get away. The confrontation, according to the victim’s account, was not a brief outburst but a sustained attack that left blood throughout the room.
Authorities say the teen ultimately fled the house and sought help from neighbors, who called emergency services as he bled from multiple injuries. Medics transported him to the Maryland Shock Trauma, where doctors documented four significant puncture wounds to his back, an injury around his neck, and cuts to his hands that appeared consistent with defensive wounds. Police later said the boy was expected to recover, a prognosis that turned what could have been a homicide into an attempted murder case.
From Substitute Teacher to Attempted Murder Defendant
Before the attack, Mui had worked as a substitute educator in Carroll County Public, moving between classrooms as needed rather than holding a permanent post. District officials have confirmed that she is no longer employed there, distancing the school system from the criminal allegations now unfolding in court. Her role as a former educator has intensified public scrutiny, since parents and students once saw her as a trusted adult in local schools.
Law enforcement officials say Mui’s transition from classroom stand-in to criminal defendant began when deputies responded to the Manchester home and found evidence of a violent struggle. According to investigators’ accounts, she was taken into custody and later charged with attempted second-degree murder and related assault counts. The teen’s survival, and his detailed description of the attack, now form the backbone of the prosecution’s case as Mui awaits further court proceedings.
A Prolonged Struggle and Alleged Murder-Suicide Plan
Charging documents describe a harrowing sequence that lasted far longer than a single burst of rage. The victim told deputies that throughout the estimated ordeal, he was not only stabbed but also strangled with a shirt and with hands pressed around his neck. Investigators say the teen recounted being pinned down as he struggled to breathe, then breaking free and fighting to reach the door while his mother tried to keep him inside the room. The length and intensity of the confrontation, as described in court records, suggest a sustained attempt to kill rather than a momentary loss of control.
Deputies say Mui later told them she intended to die alongside her son, a statement that has led officials to characterize the incident as a botched murder-suicide. In one account, she allegedly admitted that she planned to kill the boy and then herself, a detail echoed in charging documents that outline her alleged statements to investigators. Prosecutors now argue that this admission, combined with the severity of the teen’s injuries, underscores the premeditated nature of the attack.
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