Murder suspect has history of mental issues

La Plata, MD - A Charles County man charged with stabbing his mother to death in early January has a history of domestic violence and mental health issues, investigators reported. Mario Marcell Dunn, 32 of Waldorf (pictured), was arrested hours after the victim—Swanda Ruegenea Dunn, 57, also of Waldorf was found dead on Old Washington Road near Smallwood Drive.

“A check of Charles County Sheriff’s Office records indicates that Mario Dunn has a history of domestic violence arrests and psychological issues,” stated Detective J. Long, the crime’s lead investigator. “He has been previously diagnosed with paranoid schizophrenia.”

On Jan. 26 Mario Dunn was indicted in Charles County Circuit Court on one count of first-degree murder. On Tuesday, Jan. 30 a motion was made in Circuit Court for Dunn to undergo a competency evaluation, court records indicated. He remains in custody at the Charles County Detention Center.

According to Long’s statement of probable cause, when responders and investigators first located Swanda Dunn’s lifeless body, Thursday evening, Jan. 11, it was determined she was stabbed at least 10 times in her head, face, neck, chest and abdomen. “The deceased was not wearing any shoes and her feet were clean,” Long stated. “Based on blood that was on her clothing, it appeared the deceased had been in a seated position when the incident occurred. She was not in possession of any identification and her identity was initially unknown.”

The Charles County Sheriff’s Office sought the public help in identifying the dead woman, providing images of Swanda Dunn’s tattoos to the media. According to Long, the sheriff’s office was contacted Jan. 12 by Swanda Dunn’s family members who explained they were unable to contact her. “Family members identified the tattoos that were on the deceased’s left shoulder blade area and right wrist,” Long stated. “Based on photographs, tattoos and other descriptors, the deceased was positively identified as Swanda Ruegenea Dunn.” Police further learned that Swanda Dunn drove a tan Mercury Sable, resided in Waldorf with her son, Mario and both she and her son had left a family member’s house in Upper Marlboro less than an hour prior to her body being discovered in Waldorf. “Prior to leaving the home, Mario Dunn was upset and he was waving a knife around,” Long stated in court documents.

On Jan. 12 around noon, investigators made contact with Mario Dunn at his Waldorf residence. He was transported by police to the Criminal Investigations Division at the Charles County Sheriff’s Office District III Station to be interviewed. He agreed to speak with Long. According to Long’s statement of probable cause, Mario Dunn stated his mother drove the vehicle from Upper Marlboro to Waldorf, he was dropped off at the residence around 11 p.m. and his mother then drove away and didn’t return. “Mario Dunn denied killing his mother or being involved in her death,” Long stated.
Police subsequently confiscated the tennis shoes Mario Dunn was wearing  “Suspected biological evidence was observed on the back of his right Nike shoe and presumptive tests later confirmed that this was blood,” said Long. Swanda Dunn’s Mercury was located about 1.4 miles from her residence and approximately 1.5 miles from where her body was found. Long stated there was “blood evidence in the passenger compartment. The defendant is the last known person with the victim prior to her death. There is no information to suggest anyone else was with the victim after leaving her family’s home in Upper Marlboro.”

Mario Dunn is being represented by the Charles County Office of the Public Defender.

Contact Marty Madden at

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