DNA Profile and Genetic Genealogy Lead to Arrest in 2011 Murder of 13-Year-Old Girl After 15 Years

Following a breakthrough using genetic genealogy, Polish police arrested a 37-year-old man in Gdańsk for the 2011 murder of 13-year-old Izabela Strzałkowska.

Arrest and Court Decision

Officers from the Provincial Police Headquarters in Gdańsk detained Michał S. on Tuesday morning. On Wednesday afternoon, the District Court in Gdańsk remanded the suspect in the murder of 13-year-old Izabela Strzałkowska in custody. The 37-year-old faces up to life imprisonment.

The man immediately knew which crime was in question and confessed to the murder of 13-year-old Iza Strzałkowska. However, at the prosecutor’s office, aside from confessing to the murder, he refused to provide any explanations. At the time of the murder, Michał S. was 22 years old and lived near his victim in Gdynia Dąbrowa. Today, he has a wife and two preschool-aged children, worked normally, and had never been recorded by the police.

Investigation Background and Evidence

Investigators interviewed over 950 people and collected more than 900 DNA samples. The murder took place on August 23, 2011, in Gdynia. The body of the girl, who had walked her friend to a bus stop in the evening, was found in a grove in the Dąbrowa district, 300 meters from the apartment building where she lived. Officers secured the DNA profile of the potential perpetrator at the scene.

“Police officers and prosecutors conducted arduous, methodical activities for years, analyzed dozens of expert opinions, interviewed hundreds of people, secured and examined massive evidence material. However, despite the performed activities and wide-ranging analyses, the initial investigation did not lead to identifying the perpetrator and was discontinued in 2013,” describes junior compeer Anna Banaszewska from the press team of the Provincial Police Headquarters in Gdańsk.

Cold Case Revival and Breakthrough

After the Regional Prosecutor’s Office took over the case in 2020, investigators began a new, detailed analysis of the evidence material. The prosecutor and police officers from the unsolved crimes team, the so-called X-Archive of the Investigative Department and the Criminal Department of the Provincial Police Headquarters in Gdańsk, prepared thousands of further pages of documentation, interviewed a total of over 950 people, and collected over 900 DNA samples. They also obtained nearly 150 expert opinions from various specialties.

The isolated DNA profile of the perpetrator never appeared in databases. According to the prosecutor’s office, the suspect was successfully detained thanks to a DNA profile. However, the difficulty in detecting the murder perpetrator stemmed from the fact that the event occurred with no direct witnesses, and the isolated DNA profile of the perpetrator never appeared in available databases.

Genetic Genealogy and Confirmation

“Thanks to a revolutionary investigative method used for the first time in Poland, a breakthrough occurred. Cooperation with a team of experts appointed by the prosecutor in the field of genetic genealogy allowed for suspect profiling through kinship analysis in broad databases. After two years of work, a man was identified whose genetic connections and other findings indicated him as the potential perpetrator,” describes junior compeer Banaszewska.

On the prosecutor’s orders, police officers collected biological material from the detained 37-year-old and forwarded it to two independent institutions in Gdańsk and Kraków. Comparative DNA analyses confirmed a full match between the suspect’s profile and the material secured on the victim’s body in 2011.