Tylee Ryan's best friend lovingly remembers their friendship before she went missing

A tragic ending so many feared in the case of two missing kids with ties to Arizona. Seven-year-old JJ Vallow and 17-year-old Tylee Ryan were found dead underground after investigators in Idaho located their remains on Tuesday.

Their mom, Lori Vallow, has been in jail since February on suspicion of child abandonment. Her husband, Chad Daybell, reportedly tried to flee the scene where police made the grim discovery at his home.

RELATED: Attorney breaks down what Vallow, Daybell could face in court after children are found dead

Now he's locked up and being held on a $1 million bail.

One of Tylee's best friends is speaking for the first time on the warning sign she says she wished she saw.

The teen had been in Idaho for only a week before she went missing. She was last seen on Sept. 8th.

She spent a majority of her teen years in Arizona and she went to Perry High School for a short time.

Loved ones say she never wanted to move, but did so to stay with her little brother JJ.

Tylee's best friend says she lost contact with her soon after the move to Idaho. "There was definitely a shift in behavior," explained Tylee's best friend Gillian Kennedy.

RELATED: New e-mails show FBI researched podcasts done by Lori Vallow

She still looks back at the text message she sent to her best friend
on Oct. 19th. Kennedy just wanted to tell Tylee she missed her, and she says it took about a week to get a response saying "Miss you guys too - luv ya."

Kennedy had no idea Tylee and JJ had already vanished by late September. "Looking back, we should have realized something was wrong a lot sooner and I feel sorry for them. I feel like we kinda let them down in that area," Kennedy said.

Nine months later, the truth to where the kids have been was finally answered -- the backyard of their stepfather, Chad Daybell.

Kennedy misses the girl who shared the same sense of humor, loved her Jeep and was there for her constantly.

"We loved her more than anything and that pain is just a reminder of that and if that's the trade off that I get where I'm upset sometimes just because I loved her, then I'm more than willing to trade that for the memories and experiences that I had with her, for sure," Kennedy said.

As for remembering JJ, Life Academy, the school he attended in Gilbert, is holding a memorial event for him next Friday morning, June 19th.