Charles County Sheriff’s detectives arrested Mario Marchell Dunn, 32, of Waldorf, in connection with the murder of his mother, Swanda Ruegenea Dunn, 57, of Waldorf.

Swanda’s body was found on January 11, 2018, on Old Washington Road near Smallwood Drive.

Dunn is accused of stabbing his mother while they were driving home from a relative’s house. After the murder, Dunn removed his mother from the vehicle and left her in the roadway.

Dunn was arrested after detectives identified the victim and served a search warrant at her house – where her son lived – and recovered evidence linking him to the crime. A clear motive has not been established.

Dunn was charged with first-degree murder, second-degree murder, assault and other related charges.

Det. J. Long is investigating.

