Former college football player, 19, goes on trial for murdering his 16-year-old cheerleader ex-girlfriend - but he claims it was an accident while he was trying to be a hero

Former college football player, 19, goes on trial for murdering his 16-year-old cheerleader ex-girlfriend - but he claims it was an accident while he was trying to be a hero

When 16-year-old Emma Walker broke up with her 18-year-old boyfriend Riley Gaul in October 2016, her family noted that she was acting like herself again for the first time since their relationship began two years ago. The young couple's time together had been turbulent, with Gaul exhibiting controlling tendencies and sending threatening messages to Walker whenever he was angry. And soon after the breakup, he began resorting to extreme measures to get Walker's attention. One night not long after they split, he washed down a handful of Vicodin with alcohol in a supposed suicide attempt. Then, three weeks after the breakup, Walker began receiving strange messages and phone calls from an unknown number while at a friend's party. The mysterious person on the other end of the line told Walker that they had kidnapped Gaul and would hurt him if she didn't follow their orders. When she went outside, she found only Gaul himself, lying in a ditch and holding his head as if he'd been beaten. Walker seemingly recognized that the "kidnapping" was all a ploy for attention, and she told Gaul to leave her alone. But just two days later, while she was asleep in her bed, he crept just outside of her room and shot her dead. Now the story A 19-year-old former college football player has gone on trial accused of murdering his ex-girlfriend by shooting through her bedroom wall. William Riley Gaul, who attended Maryville College in Tennessee, is accused of killing Emma Walker more than a year-and-a-half ago. Gaul killed the 16-year-old while she was sleeping in her bed in the early hours of November 21, 2016, by firing two shots through her bedroom wall from outside the house. Her mother found her dead the next morning. While both sides in the trial in Knoxville agree that Gaul killed Walker, his lawyers say the shooting was an accident - part of a plot to get her back. Gaul's lawyers said he shot at the bedroom to try and frighten Walker, so that she would call him for help and he could run to her 'rescue' and be her 'hero'. They claim he didn't know bullets could pierce through walls. They say he can't be found guilty of first-degree murder since he never intended to kill Walker. 'Intentionally doing an act and intending to kill are two entirely different things,' defense attorney Wesley Stone said in his opening statement on Tuesday. 'I think throughout this trial, that distinction will become apparent.' But Knox County Assistant District Attorney Kevin Allen called Gaul a 'premeditated cold-hearted killer'. He said Gaul fatally shot Walker, aiming directly at where she was sleeping in bed, in anger over the end of their tumultuous two-year relationship. Walker's mother Jill was among the first to take the stand on Tuesday, on the first day of the trial. She spoke about how her daughter started dating Gaul when she was a freshman and he was a junior at Central High School. 'In the first couple months it was fine,' Jill Walker testified this week. 'It seemed normal. We kept a close eye, she was only 14 years old at the time.' But Jill and her husband Mark monitored their daughter's messaging apps and didn't like the way that Gaul was speaking to her. 'Some of the language and the way she was spoken to, we didn't think it was appropriate — to speak to anyone like that,' she said. 'We tried to discourage her from seeing him. We would set limits how and when they could see each other.' When Gaul left for college at the beginning of the 2016-2017 school year, they hoped the two would break up. But their daughter was 'stubborn' and the relationship continued off-and-on for a period. Finally, it was Walker who decided to end things not long before her death. 'She had chosen to move on,' Jenny Weldon, Emma's aunt, told the court. 'He refused to accept it. He chose not to accept her wishes.' On Tuesday, five of Walker's friends testified about a strange interaction they had with Gaul the Friday before Walker's death. The group of friends was having a sleepover after a Friday football game when Walker started getting strange text messages from an unknown number. 'Go to your car with your keys,' the first text read. 'Go alone … I've got someone you love. If you don't comply I will hurt them.' Walker showed the text to friend Zach Greene, and they walked outside together but saw nothing. Then another text message came in. 'What part of alone wasn't clear? I don't want to hurt a loved one.' At this point, Greene says Walker began to suspect that it was one of Gaul's friends who was sending the texts, and she responded saying as much. 'I'm no one's friend,' the texter replied. 'We have him now … If you don't care about him anymore then it shouldn't bother you. Call the police, and he dies. Your choice … If you'd like to hear his final screams, give me a call. He's in a ditch beside (the) house. It's a shame you can all of a sudden not value someone's life.' This time Walker and Greene were accompanied outside by a larger group of friends, and found Gaul lying on the ground. He then claimed he had been kidnapped. 'He told me he was hit over the head, and he didn't recall anything,' Hailey McDonald, a senior at Central, testified Wednesday. 'But then later he remembered (the kidnappers) said, "Call Emma." I told her it was probably made up. It was the type of behavior he'd exhibited before.' Walker went back inside and Gaul walked away. Friends say Walker seemed frightened and angry. While Gaul claimed that the kidnappers stole his phone, he soon started texting McDonald at the slumber party. 'My head is throbbing,' he wrote. 'I have no (expletive) idea what happened. I literally woke up in her yard … I could have been killed, and Emma didn't even give a (expletive).' Gaul later admitted to police that he made up the story about being kidnapped. After the failed attempt to win back Walker's affections, Gaul moved onto a more sinister plan, prosecutors say. The next day, they say he dressed in all black and walked over to her house and started knocking on the door - scaring Walker, who was home alone Gaul continues to deny that the 'man in black' was him - but Walker's friend McDonald says she 'immediately knew it was Riley' when Walker texted her about the incident. McDonald says she also saw Gaul's car parked at a swimming pool near Walker's house around this time. 'I immediately texted him and asked why he was in Sterchi,' she said. 'He freaked out. He denied it.' But Walker bought his story. 'It wasn't Riley,' Walker texted her friends. 'He texted me, speeding over here.' Prosecutors say Gaul came over to comfort Walker, playing the role of 'rescuer'. But Walker's mother returned home soon after and ordered him to leave. Walker died when Gaul came back later that night, in the early hours of November 21, and fired two shots through her bedroom wall. Gaul's defense attorney said that he didn't know that a bullet could travel through a wall, and only meant to frighten her, so he could come back and pretend to save her. Prosecutors were expected to counter that claim on Thursday, with two of Gaul's friends scheduled to take the stand and explain his efforts to try and dump his grandfather's stolen gun in the Tennessee River after the shooting. Gaul's grandfather, James Walker (no relation to Emma), was the last witness to speak in court on Wednesday. He told the court about how he noticed his gun was stolen on November 18, after briefly switching cars with his grandson so that the tires could get repaired. When he drove his own car home, he noticed that the gun was missing from where he usually stored it underneath the driver's seat, and informed the Knox County Sheriff's office. He said he feared that his grandson might have taken it, and that he might use it to hurt himself, since friends had told him they were worried about Gaul. But he never thought his grandson was a danger to others. When he learned of Walker's death, he never suspect his grandson. 'That never crossed my mind that Riley would hurt her... never crossed my mind. That wasn't him,' said James Walker. Gaul faces the possibility of life in prison without parole if convicted of first-degree murder. Gaul was dismissed from the Maryville football team after he was arrested.