A police officer and more students took the stand Wednesday on day four in the trial of a Bronx teenager accused of stabbing his classmate to death at school.

The police officer from the 48 Precinct was likely the last person to see Matthew McRee alive. She told the court she saw blood on the floor and walls of the school and that McRee was leaning against a wall bleeding from his chest.

 She added that she tended to him before an ambulance got to the Urban Assembly of School for Wildlife Conservation on Sept. 27, 2017.

McRee’s mother says she finds comfort knowing her son didn't die alone.

“She helped somewhat to know that someone was there to care for my son and that she was really concerned about condition of my son, so I just want to thank her on that” said McRee’s mother.

Cedeno has admitted to stabbing McRee. A video played by the prosecution showed Cedeno telling police that McRee punched him on the left side of his cheek followed by two more punches before Cedeno says he stabbed him.

On Tuesday, a teacher testified that McRee threw the first punch.

A special-education teacher also took the stand testifying that he tried to stop MCree from approaching Cedeno, but McRee pushed him away and began to argue with Cedeno.

Testimony in the case is scheduled to resume on Monday.

MORE: Prosecution’s star witness takes stand in Cedeno school stabbing trial , Family of teen fatally stabbed in classroom prepares for trial , Cedeno to take stand in his own defense in fatal school stabbing trial , Classmates testify in deadly school stabbing trial , Trial begins for Bronx teen accused of fatally stabbing classmate , Judge considers confession video evidence in 2017 fatal school stabbing