TULSA, Oklahoma - A grieving family says whoever killed 16-year-old Darrin Wilson is a coward for not stepping up and taking responsibility.

Wilson’s family visits him at his gravesite at least once a week. They say they constantly feel his presence around them so it's important for them to make sure he's not alone.

"I just want to know why,” said his 12-year-old sister Elisa Wilson. “Like, did he do something wrong?”

It's a painful but simple question his family just can't seem to get answered.

"I do miss my brother,” said Elisa.

And the sting of it still hits hard, so for now, Darrin’s family will cry, lean on each other and continue to visit his gravesite.

"We have fun; we don't just cry,” said his grandmother Edith Gilbert. “We come out here, we talk to him and sometimes he talks to us."

They call him Da-Da.

His grandmother says when anything out of the ordinary happens near his gravesite, like the wind blows something away or somethings falls, it's him telling them things will be ok.

"It's like he's holding us right now, trying to hold us together,” she said.

On June 8, police found his body abandoned on an East Tulsa trail. And two months later, who did it remains and unsolved mystery.

"This way was devastating, totally devastating to our family,” said Gilbert.

She says it took her a while to believe the devastating news because 16-year-olds with a personality and smile like his shouldn't die like this.

"He gave me a hug and told me, and he told me Granny I love you,” she said.

The idea that they can't touch him, can't talk to him hurts. They find some comfort knowing he's somewhere better with other family members who have passed on but say they still need more than comfort.

"We want justice for our baby, for our Da-Da,” said Gilbert.

If Darrin was still alive he would turn 17 next month, so his family is asking anyone with information to contact police.