The Białystok Nurse Murder Cold Case

The victim, a 30-year-old nurse identified in reliable Polish reporting as Agnieszka D., was attacked in August 2001 on Białystok's Sienkiewicza housing estate, close to her home. She survived the initial assault but never recovered and died in hospital months later.

A case that went cold

Investigators gathered evidence in 2001, but the offender was not identified and convicted at the time. The case remained unresolved for roughly two decades.

Years later, officers from the Podlaskie police cold-case unit known as Archiwum X reopened and reworked the investigation with prosecutors. Official police reporting states that they identified a suspect and traced him to England.

Arrest in England and return to Poland

In June 2021, British authorities detained the man later prosecuted as Mariusz P. Polish police reported that he had been living in England for more than 15 years. After extradition proceedings, he was returned to Poland in early 2022 and charged in connection with the attack, rape and resulting homicide.

Mariusz P. did not admit guilt. That denial is part of the record and is not erased by the later conviction.

Trial and first-instance sentence

On January 19, 2023, the Regional Court in Białystok convicted Mariusz P. and sentenced him to 25 years in prison. The court found him criminally responsible for the rape and homicide.

Both sides challenged aspects of the judgment. The defense disputed criminal responsibility and sought a different outcome; prosecutors considered 25 years too lenient and sought life imprisonment.

Final appeal and Supreme Court review

On May 29, 2023, the Court of Appeal in Białystok upheld the 25-year sentence. Polish reporting described that judgment as final in the ordinary appellate process.

The defense then filed a cassation appeal. On December 11, 2023, Poland's Supreme Court rejected it as manifestly unfounded. That decision left the conviction and 25-year sentence in place.

Why this is a cold-case milestone

The case illustrates how old evidence can remain useful when investigators return to it with newer forensic methods and renewed cross-border cooperation. Official police reporting credits the Archiwum X team and prosecutors with identifying the suspect and locating him abroad.

It also illustrates an important editorial distinction: the police described the cold case as solved after the arrest, but this archive classifies it as solved only after the subsequent conviction, appellate judgment and Supreme Court decision.

Timeline

1. August 2001
   Agnieszka D. is attacked

   The 30-year-old nurse is attacked near her home in Białystok. She is hospitalized and later dies from her injuries.

2. June 2021
   Cold-case suspect detained in England

   After a renewed Archiwum X investigation, Mariusz P. is located and detained abroad.

3. Early 2022
   Extradition to Poland

   Mariusz P. is returned to Poland and formally prosecuted.

4. January 19, 2023
   25-year sentence

   The Regional Court in Białystok convicts him and imposes 25 years in prison.

5. May 29, 2023
   Appeal court upholds judgment

   The Court of Appeal maintains the conviction and sentence.

6. December 11, 2023
   Supreme Court rejects cassation

   The Supreme Court dismisses the defense's cassation challenge, leaving the final judgment intact.

Current status

The case is classified Solved / Adjudicated. Mariusz P. stands finally convicted and sentenced to 25 years in prison.