In that case, Andrew Lester, 84, opened fire on 16-year-old Ralph Yarl as the teen stood at Lester’s front door before any words had been exchanged, according to a probable cause document obtained by CNN. Lester, who told police he thought the teen was trying to break in, faces two felony charges in a case that touches on so-called “stand your ground” laws, the proliferation of firearms and racial bias.

In the New York shooting, both Monahan and Gillis are White. No one is believed to have exited the car, and there was no interaction between Monahan and anyone in the vehicle before shots were fired, Murphy said.

“There was clearly no threat from anyone in the vehicle. There was no reason for Mr. Monahan to feel threatened,” Murphy said.

After the shots were fired, Gillis and the rest of the group drove away from the house in the town of Hebron looking for cell phone service and then called 911.

They were found around 5 miles away from the home in the nearby town of Salem. First responders began administering CPR but Gillis was pronounced dead at the scene, Murphy said.

Shooting suspect was uncooperative, sheriff says

Police officers later responded to the home from which shots were fired and found Monahan to be uncooperative, Murphy said, adding he “refused to exit his residence to speak with police.”

He was taken into custody hours later with help from the New York State Police Special Operations Response Team, according to a press release from the Washington County Sheriff’s office.

Monahan was in custody Monday and will have a court appearance “in the near future,” Murphy said.

“This is a very sad case of some young adults that were looking for a friend’s house and ended up at this man’s house who decided to come out with a firearm and discharge it,” the sheriff said.

Speaking to CNN on Tuesday, Murphy said Monahan had not made any statement about the shooting and obtained a lawyer before he came out of the house.

“(He), quite frankly, has not shown any remorse in this case,” he said.

Gillis was an honors student who loved art and Disney and had planned to attend college in Florida studying marine biology, said Murphy, a friend of the victim’s family.

“A case like this is absolutely senseless,” the sheriff said.

Over $50,000 has been raised for Gillis’ family in a GoFundMe raising money for the “Gillis family for use toward Kaylin’s funeral expenses and any immediate financial needs,” according to the page.

“On behalf of the Gillis family, we would like to thank everyone who has offered their love and prayers as they embark on this incredibly difficult journey of grief and healing,” the GoFundMe page reads.

CNN’s Eric Levenson and Kristina Sgueglia contributed to this report.