A woman was fatally struck and allegedly "decapitated" by an MTA bus in Prospect Lefferts Garden on Saturday afternoon. Police say the victim ran toward an MTA bus near Nostrand Avenue and Lincoln Road.

The unidentified pedestrian was in her 30s, police say, and was found unconscious with severe trauma to her head and body. She was pronounced dead at the scene just before 3 p.m.

According to a police spokesperson, the woman was "observed running into oncoming traffic and apparently laid down under an MTA bus."

A person who observed the aftermath of the collision told Gothamist that "the deceased's brain was completely ejected from the body."

PIX11 interviewed one witness who said, "I saw her running but I didn't know when the bus hit her. I heard the impact, you know, and then saw her on the street."

Another witness told the Daily News that the woman threw herself under the rear bus tire and was decapitated.

"She was shaking 20 or 30 seconds, and she stopped," Furis Al-Saleh, who works at a nearby deli, said to the News. "It really broke my heart. I don't know how I'm going to sleep tonight."

The bus driver remained at the scene following the collision. Police are investigating the woman's death as a suicide.

If someone you know exhibits warning signs of suicide: do not leave the person alone; remove any firearms, alcohol, drugs or sharp objects that could be used in a suicide attempt; and call the U.S. National Suicide Prevention Lifeline at 800-273-TALK (8255) or take the person to an emergency room or seek help from a medical or mental health professional.