International hoops - What's the rule?

[mick]

Yesterday, I checked out the Pan-Am games briefly, once I found them on our Canadian channel across Gitchee Gumee.

Women's game Canada and Cuba.
Canada's ball for a front court, endline throw-in.

Ca1 saw Cu1 facing another player, away from Ca1, about 6' off the endline. Ca1 threw the ball off Cu1's glutius maximus, ran in-bounds, retreived the ball on the first bounce, and started to elevate for an 8' jumper when the whistle blew.

There was no explanation of why the whistle blew by the Canadian announcers, who are typically better-versed in sports that are very cold. Maybe something happened off-ball.

Is that thrown-in legal, or illegal, when the trapezoidal free-throw lane is used?

mick