When a 17-year-old murder suspect was charged as an adult on Tuesday, prosecutors filed a revised probable cause statement that says the murder victim tried to help the teenager before he killed her. Those details were not released last fall when Trystan Westrip was charged for the murder in juvenile court.

Westrip is charged with first-degree murder, armed criminal action, first-degree tampering with a motor vehicle, and second-degree attempted arson. He’s charged with killing and robbing Mary Shisler, 80, and then trying to burn down her home near Strafford in October.

The probable cause statement says a neighbor called 9-1-1 on Oct. 21 after finding a strange car in the driveway of Shisler’s home on Farm Road 223, seeing that Shisler’s pickup was not there, finding the back door open, smelling propane or gasoline, and finding the home ransacked.

Deputies arrived, did a quick search, smelled “the strong odor of some type of fuel or accelerant,” and didn’t find Shisler in the home. They found a bottle of lighter fluid on the kitchen table, and “some toilet paper with a match sticking up from it also on the table. On the way out of the residence, Deputies located two spots of possible blood on the inside of the door, near the door handle,” the probable cause statement says.

Deputies checked the VIN on the strange car in the driveway and found it belonged to Westrip, who was reported as a runaway from his home in Republic. They put out a broadcast for officers to be on the lookout for Shisler’s pickup. That led to a state trooper stopping it in Marshfield and finding Westrip driving it. During the arrest, the trooper reported Westrip said “he killed the ‘old lady’ who the truck belonged to and drug her body into a field, close to the residence,” according to the probable cause statement.

Officers took Westrip back to Shisler’s home and he quickly pointed out where her body was. Detectives said the body had “multiple stab wounds to her head.” Officers took him back to the sheriff’s office in Springfield, where he was interviewed in the presence of a juvenile officer and his stepfather.

Westrip’s account of what happened is in the probable cause statement, but was not released last fall by the juvenile court.

Westrip said he ran away from home on the morning of Oct. 21 after a fight with his parents. After making a couple of stops in his 1995 Subaru Impreza, he decided he couldn’t make it to Canada as planned. That’s when he drove some back roads “until he spotted a house that appeared to be abandoned, with a Dodge Dakota in the driveway” and he pulled into the driveway.

Westrip said Shisler came out to talk to him, and he put a knife in his pocket “in case he needed it.” He said she offered to take him to a gas station and buy him some gasoline. He said he didn’t want to go, so he parked behind her pickup so she couldn’t leave. They then went into the home.

Inside the home, Shisler let him make some calls on her home phone and cell phone, which he said he pretended to do. Shisler then said she wanted to walk to her neighbor’s home to see if the neighbor could help. As they were walking along the road, with her in front of him, according to the probable cause statement, Westrip said he stabbed her in the left temple. He helped her to the ground, saw she was still breathing, and stabbed her in the head again.

Westrip said he then dragged her body into a field to try to hide it. He saw Shisler’s body twitch, so he said he stabbed her about seven more times in the head. Because her pants had come down while he dragged her, Westrip said he took off his blood-spattered shirt and put it over her body.

Westrip said he walked back to Shisler’s home, took some items from a shed, kicked in the door to the home, and took “some nails, some syringes, medications, (Shisler’s) purse and a bond handled knife from inside the house.” He put the stolen items in her truck, and put everything from his car in her truck.

Westrip said he took a bottle of lighter fluid from his car and took it inside, where he poured it all over the floors and turned on a gas heater and a stove. He said he also soaked some toilet paper in gasoline and placed it on the kitchen table, lit a match and drove away, thinking that the home was about to burn. When he didn’t see smoke as he drove away, “he realized his plan to burn down the residence had not worked.”

From there, Westrip said he drove to Marshfield, “stopped a few places, including a camp, where he stole a firearm, prior to being stopped by law enforcement and detained.”

Westrip is being held without bond. He’s represented by an attorney from the Missouri Public Defender’s Capital Crimes office in Kansas City. If he’s convicted of first-degree murder, he’ll get a life prison sentence. He was 16 at the time of the murder, and Supreme Court rulings say teenagers are not eligible for a death penalty, and not automatically eligible for never being eligible for parole.

At the hearing on Tuesday in which Westrip was certified to be tried as an adult, Westrip's former probation officer testified that Westrip first got into trouble just more than a year ago for drug possession, then shortly after that for theft, and then was caught with drugs again, including Oxycodone and Xanax. The probation officer said Westrip was not successful in the juvenile department’s most structured program, and, when receiving substance abuse treatment through Burrell Mental Health, the staff asked that he be removed because of noncompliance and disrespect. The judge also heard at the hearing that Westrip assaulted his own mother shortly before the murder.