A Pennsylvania man is currently facing trial for allegedly murdering his ex-girlfriend just minutes after she ended their relationship, reportedly using the intervening time to search online for information about operating a firearm, according to authorities.

Michael Dutkiewicz, 26, has been charged with first-degree murder, third-degree murder, and possession of an instrument of crime in connection with the death of 25-year-old Alyssa Wiest. Though the tragic incident occurred in May, the trial proceedings in a Montgomery County courtroom this week have revealed more about the distressing circumstances, as prosecutors laid out their case.

Prosecutors disclosed that Dutkiewicz and Wiest, who had been a couple for two years, were out for drinks on the night of May 17, according to a report from Philadelphia’s Fox affiliate WTXF. After returning home, Wiest announced her decision to break up with Dutkiewicz—a decision her sister said had been under consideration since March, but was postponed until after a family trip financed by Dutkiewicz’s family.

Following the breakup, Dutkiewicz allegedly turned to the internet for guidance, researching how to load and fire a revolver. Shortly after midnight, he allegedly acted on this newfound information.

Officers from the West Conshohocken Police Department responded to a call at around 12:25 a.m. on May 18. Upon arrival at the residence located on the 200 block of Moorehead Avenue, they discovered Alyssa Wiest lying face down on the sidewalk, suffering from apparent gunshot wounds to her torso, as reported by the Montgomery County District Attorney’s Office.

West Conshohocken police officers reported being called to a residence on the 200 block of Moorehead Avenue at about 12:25 a.m. on May 18. When they arrived, they found “a female, later identified as Alyssa Wiest, face down on the sidewalk, with obvious gunshot wounds to her torso,” the Montgomery County District Attorney’s Office said.

She was brought to a nearby hospital, where she was pronounced dead. Dutkiewicz is alleged to have shot and killed her just 25 minutes or so after she broke up with him — using the victim’s own personal revolver, prosecutors say.

Detectives launched a homicide investigation, and prosecutors said they found several pieces of evidence. For one, the door to Wiest’s home, “a few doors from where she was found, was ajar, and there was blood found both inside her residence and along the sidewalk leading to her body.” Five “projectiles” were also recovered, both inside the home and outside by her body.

In court this week, neighbors reportedly described the gunshots and Wiest’s screams as she ran down the sidewalk in an apparent attempt to get away from her attacker.

Investigators said that “immediately after the shooting, a neighbor saw Dutkiewicz standing by his silver Ford F-150 truck” — and then the truck left the area. License plate readers confirmed that a truck belonging to Dutkiewicz was driving from West Conshohocken and through Conshohocken at 12:25 a.m. that night, authorities said.

A warrant was later issued for his arrest, and he turned himself in. He was placed in the Montgomery County Correctional Facility.

Dutkiewicz’s defense team is not disputing who committed the killing, but rather arguing that the attack was caused by a sudden emotional moment and not premeditated, according to WTXF. Video evidence is expected as the trial continues, and a jury could deliberate as soon as Thursday.

Wiest’s obituary describes her as “our beloved shining star—radiant, vibrant, and full of light. Her presence lit up every room she entered, and her absence leaves a deep ache in the hearts of all who knew and loved her.”