Yellowknife RCMP are investigating after a 14-year-old boy was allegedly assaulted and robbed on the Frame Lake Trail Sunday night at approximately 10 p.m.

Liam Silke was walking along the trail with four other teenage boys after going to McDonald's. His sister Summer says he knew two of the boys.

She says the two boys Liam didn't know attacked and robbed him on the hill below Gitzel Street.

"One jumped on his back and started to chokehold him," she said.

"His two friends just thought it was a joke at first and then they realized it was serious."

Silke says her brother held up his wallet, fearing that one of the boys might have a weapon. She says the two boys took it and ran off. The wallet contained $100 in cash, a gift card and Liam's school ID.

Summer says she found the empty wallet on the family's front porch Tuesday morning and took it to police.