A 17-year-old boy accused of fatally shooting another teen Sunday in South St. Paul has been charged with three counts of second-degree murder and prosecutors filed a motion seeking to try him as an adult.

Casimir Anthony Semlak of St. Paul was charged Wednesday by juvenile petition in connection with the death of Anthony Skelley, 17, the Dakota County Attorney's Office said.

The charges include the felonies of intent but not premeditated murder, a drive-by shooting and commission of a crime of violence at the time he caused a person's death.

Semlak made an appearance in juvenile court Wednesday where prosecutors sought to have him certified as an adult, the Attorney's Office said.

Officers arrived on the 1900 block of Conver Avenue about 10:40 p.m. and found Skelley with no pulse, not breathing and gunshot wounds to his head, torso and shoulder. Officers attempted lifesaving measures, but Skelley was pronounced dead at the scene. The Hennepin County Medical Examiner's Office listed his official cause of death as "multiple gunshot wounds."

Skelley was also holding a BB gun in his hand and police found a cellphone and small bag of marijuana near him as he lay in the street, according to the petition filed in Dakota County District Court. Police also found shell casings from a 9-millimeter handgun near Skelley, the petition said.

Investigators looked at Skelley's cellphone and determined the last call was linked to Semlak. They also found a string of text messages between the two teens concerning the sale of marijuana, including the last one from Semlak that said "here," the petition states.

Several neighbors reported gunshots to 911 and saw a white or silver four-door vehicle with a damaged right taillight speeding away from the scene. Videos obtained from neighbors' doorbell camera systems caught portions of the incident and the vehicle matching the description leaving the area, the petition said.

Investigators traced a phone number linked with a money-transfer app to Semlak. Police found Semlak in St. Paul and arrested him Monday. At that time, Semlak possessed a Springfield 9mm Hellcat handgun containing several bullets, which were the same brand as shell casings found at the scene. He also had the phone used to exchange messages with Skelley, the petition said.

"Given the seriousness of the offense and the age of Casimir Semlak, my office has filed a motion for certification seeking to prosecute him as an adult," said Dakota County Attorney Kathy Keena. "Our deepest sympathy is extended to the family and friends of Anthony Skelley for their great loss."

Semlak will be held in the Dakota County Juvenile Detention Center until his next court appearance Tuesday