Brooke McLaughlin, 14, lived at this house on Blackberry Road in Mount Vernon with her boyfriend, Aidan Grant. A hearing is being held this week in Waterville to determine if Grant, now 16, will be tried as a juvenile or an adult in McLaughlin’s July 2022 death. Derek Davis/Portland Press Herald file

WATERVILLE — A judge now will determine whether 16-year-old Aidan Grant will be tried as a juvenile or as an adult on a murder charge in the death last year of his girlfriend, Brooke McLaughlin.

District Court Judge Andrew Benson heard final testimony Thursday in a hearing that lasted more than two days, and his decision is expected to be rendered in October.

Grant was 15 on July 18, 2022, when prosecutors say he stabbed McLaughlin 10 times in McLaughlin’s Mount Vernon home where they lived together with her mother, according to testimony. Grant initially denied killing her but later confessed to a sergeant at Long Creek Youth Development Center in South Portland where he is being detained.

Testimony in Waterville District Court this week showed that Grant and the 14-year-old McLaughlin were living in the mobile home and having a sexual relationship while mostly making their own meals and getting themselves to school. On the day of the killing, Grant had been drinking vodka and smoking marijuana and they got into an argument about prior relationships with other people. The altercation then turned physical.

The final witness called by Assistant Attorney General Katie Sibley on Thursday was George Ryan Pennington, a sergeant at Long Creek who is in charge of safety and security of the building, staff and residents. He said that on July 23, 2022, Grant told him he wanted to talk with him, with Pennington telling Grant that he would have to report to authorities whatever he said because he is required to report such information.

Grant told Pennington that he and McLaughlin were sitting on a couch and smoking marijuana in the mobile home July 18, which was Grant’s birthday. She was texting an ex-boyfriend and he was texting an ex-girlfriend.

“And at some point she became upset about that and he mentioned that she had been more aggravated lately because she wasn’t taking her meds, and that during the aggravation she was becoming physically and verbally assaultive,” Pennington said.

He said Grant told him McLaughlin got on top of him on the couch, he saw a knife on a nearby birthday cake and stabbed her with it. Grant said he then made phone calls, one of which was to McLaughlin’s mother, according to Pennington.

Brooke McLaughlin Courtesy photo

Sibley asked Pennington if he ever remembered Grant saying his girlfriend’s name at any time. Pennington said he did not. Pennington testified that Grant told him he had never told anyone else about what happened that day.

Sibley’s questioning earlier in the week revealed that in Grant’s phone call to McLaughlin’s mother, which lasted more than 10 minutes, he told her Brooke wanted to know when she would be coming home, when actually the teen was already dead.

John Pelletier, Grant’s court-appointed attorney, has not disputed that Grant was responsible for her death, but said it was not premeditated. Pelletier asked Pennington on Thursday to tell the court how Grant responded when Pennington asked how he was feeling after confessing to the stabbing.

“He said he felt like he could breathe,” Pennington recalled.

Prior to that day, Grant’s version of the killing kept changing. At first he told authorities that an intruder had come into the home and was holding something, and Grant panicked and fled.

But testimony from law enforcement officials revealed he had taken a red Chevrolet Impala belonging to McLaughlin’s mother, driven through several towns and then parked in a sandpit about 100 yards from his father’s home in Wayne. Footprints from the car indicated he walked to the tree line and eventually arrived at that home.

Sibley sought to show during testimony that there was not a birthday cake or knife where Grant said they were and that McLaughlin’s mother brought the cake home later in the evening, after 6 p.m. That is when she found a knife on the kitchen table and her daughter unresponsive and lying face down on the living room floor.

Grant was described during testimony as a submissive, passive boy who was good to McLaughlin, opened doors and carried things for her and had a good relationship with her mother. He suffered from severe anxiety and smoked marijuana to feel better, and used alcohol, witnesses said. His parents, who are divorced, are supportive of him, as are his brothers, according to testimony.

Sibley asked Pennington on Thursday what his relationship with Grant is like at Long Creek.

“Fairly good,” Pennington said. “He’s one of the best residents I have.”

If Grant is to be tried as a juvenile, his case would be heard in juvenile court where decisions would be made about what happens next. He could stay in Long Creek until he is 21 and would receive mental health treatment and learn life skills. Two forensic psychologists who testified said they thought five years would be an adequate time for him to be rehabilitated. Defense testimony described Grant’s actions as “heat of the moment.” Witnesses said he and McLaughlin were youths engaging in adult behaviors and neither had the tools to deal with their situation, including their emotions.

If Grant is to be tried as an adult, the case would go to Superior Court. A minimum sentence for a murder conviction is 25 years.

Benson, the judge, requested Pelletier submit a proposal argument to the court by Sept. 22. He requested Sibley submit a response to that proposal by Oct. 6, shortly after which Benson said he would make a decision. Benson apologized for the delay in the court process, saying he wanted to make sure that both sides have adequate time to prepare their written documents.