ST. CHARLES, Mo. (AP) — Prosecutors say a Missouri man charged with fatally shooting his girlfriend, her two young children and her mother could face the death penalty once the investigation is complete.

Authorities are still investigating what led to the shooting late Friday. Richard Darren Emery of St. Charles, Missouri, is facing 15 charges, including first-degree murder.

Emery, who often goes by his middle name Darren, exchanged gunfire with officers as he fled. He was captured several hours later — wounded and covered in blood.

St. Charles is a city of about 70,000 residents on the Missouri River northwest of St. Louis.

A candlelight vigil was planned Sunday evening to honor the victims: 61-year-old Jane Moeckel, 39-year-old Kate Kasten, 8-year-old Zoe Kasten and 10-year-old Jonathan Kasten.