A 20-year-old St. Paul man pleaded guilty Tuesday to fatally shooting a teen during a marijuana deal in South St. Paul in 2022.

Casimir Anthony Semlak was 17 when he shot Anthony John Skelley outside Skelley’s home on May 8, 2022. Skelley, also 17, suffered gunshot wounds to his head, torso and shoulder and died at the scene. Skelley was selling marijuana to Semlak at the time of the shooting, investigators believe.

Four days after the killing, Semlak was charged by juvenile petition in Dakota County District Court with three counts of murder. He was certified to stand trial as an adult last year.

Semlak pleaded guilty to second-degree murder by drive-by shooting after reaching an agreement with the prosecution last week. The plea agreement calls for a 17-year prison term, which would be a downward departure from state sentencing guidelines.

One count each of second-degree intentional murder, not premeditated, and second-degree unintentional murder while committing a felony will be dismissed at sentencing, which is scheduled for Jan. 14.

Semlak’s attorney did not return a call requesting comment Tuesday afternoon.

According to Skelley’s family, he was a junior at Gateway to College, a St. Paul Public Schools program at St. Paul College that allows high school students to earn college credits. Before that, he went to Two Rivers High School — formerly Henry Sibley — in Mendota Heights.

“Anthony was an ambitious young man and had big plans for his life,” his obituary read. “He loved to work on cars, mow lawns and landscape during the summer, and could fix or install just about anything. His dream was to start his own business and he began to focus his efforts in areas he was skilled — landscaping and car repair and sales.”

Neighbors reported gunshots

South St. Paul police officers responded to a shots-fired report in the 1900 block of Conver Avenue around 10:42 p.m. and found Skelley lying in the street unresponsive, not breathing and without a pulse.

Officers found a BB gun in Skelley’s hand, according to the criminal complaint, and shell casings from a 9mm gun near him. A cellphone and a small bag of marijuana were found nearby in the street.

Neighbors reported hearing gunshots and seeing a small white or silver four-door car with a damaged right taillight leaving the area at a high rate of speed. Several Ring camera videos showed portions of the incident and the car in front of Skelley’s home.

During a search of his bedroom, investigators found marijuana in several bags and jars, the complaint says.

A male who had been inside Skelley’s home at the time of the shooting told officers he heard him on the phone saying that he would go outside. He was shot a short time later.

A search of Skelley’s cellphone showed the last number called was to Semlak, the complaint says.

The phone also revealed a string of texts between the two teens about the sale of marijuana. In one text, Skelley gave Semlak his home address. The last text Skelley received from Semlak read “here.”

Investigators identified Semlak as the marijuana buyer through Cash App, which was on Skelley’s phone, the complaint says.

When Semlak was located and arrested at a St. Paul park, he was in possession of a Springfield 9mm Hellcat handgun with an inserted magazine containing several bullets. The bullets in the magazine were the same brand as the shell casings found at the scene of the shooting. Semlak’s DNA was found on the gun’s handgrip.

Semlak also had with him the cellphone that exchanged messages with Skelley.

He declined to provide a statement to investigators.