A Missouri man was charged with four counts of murder for allegedly gunning down his girlfriend, her two children and her mother at their home, authorities said Saturday.

Richard Emery, 46, faces a total of 15 charges, including first-degree murder, assault and attempted robbery, St. Charles County Prosecuting Attorney Tim Lohmar said at a news conference Saturday.

In the master bedroom of the home where the shooting occurred, officers found a 39-year-old woman — identified as Kate Kasten — still alive but in critical condition, Lohmar said. In a downstairs bedroom they found the bodies of a 61-year-old woman, an 8-year-old girl and a 10-year-old boy, he said.

The 39-year-old woman later died at a hospital, according to a probable cause statement from the St. Charles Police Department.. The other victims were identified as Kasten's two children Zoe, 8, and Jonathan, 10, and her mother, Jane Moeckel, 61.

Emery allegedly shot and killed the four at the home they all lived in together just before midnight on Friday before fleeing in his pickup truck and shooting at police officers responding to the scene, Lohmar said.

“One of the bullet holes from the subject’s gun pierced the door frame right in front of where one of the two officers was standing,” the prosecuting attorney said.

Richard Darren Emery and Kate Kasten via Facebook

Emery eventually left his truck and allegedly tried unsuccessfully to carjack a woman driver, stabbing her, he said. The woman, whose description of the suspect’s clothing matched Emery’s, is recovering from her injuries, Lohmar said.

The woman, who had been stabbed multiple times in the torso, was taken to a local hospital, according to the probable cause statement.

Police then led a “massive manhunt” for Emery and found him in a bathroom at a local gas station about two miles from the scene of the shooting, Lohmar said.

“He was bleeding profusely and suffering from what appeared to be gunshot wounds,” he said, adding it was reasonable to assume the gunshot wounds came from the shootout with police officers.

Richard Darren Emery St. Charles Police Department

After being taken into custody, Emery allegedly asked, "Is the lady OK?," referring to the woman he tried to carjack, according to the probable cause statement.

While detectives were sitting in a trauma room of a hospital with Emery, he allegedly asked, "Are you the officers I shot at?," according to the statement. The detectives told him they were not, but that they were friends with those officers. Emery then asked if he hit any of the officers and apologized for shooting at them, according to the statement.

Lohmar said the investigation was ongoing and the motive for the killings was still unknown.

“We may never know,” he said.

Lohmar said there had been a “series of violent crimes” in the area in the last few months that were unrelated to each other but were all domestic violence incidents.

“This one in particular was the worst example of a domestic violence case,” he said. “Anytime you have a domestic violence case you worry about the safety of the victim, and this would be your worst nightmare that something like this could happen.”

There had been no previous domestic-violence calls at the home where the shooting occurred.

Police said they recovered a 9 mm gun and a knife near the scene and that Emery was on the run for about seven and a half hours before he was caught.