MIAMI (AP/CNN) — An attorney for the family of an 18-month-old Indiana girl who fell to her death from the 11th story of a cruise ship in Puerto Rico says she plunged from a window inexplicably left open in a children’s play area.

Attorney Michael Winkleman in Miami said in a statement Tuesday that Chloe Wiegand was playing in the “kid’s water zone” on the Freedom of the Seas on Sunday when she asked to be lifted to a wall of windows lining the play area so she could bang on the glass.

“He literally thought there was glass there and he thought she was going to bang on the glass like she was at a hockey game like she’d love to do with her brother,” Winkleman said. “And she goes to bang on the glass, and the next thing you know, she’s gone.”

He says Chloe’s grandfather lifted her, believing the window was closed, and “she was gone in an instant.”

Winkleman says the family wants to know why a window that “should have been closed securely” was open.

“I mean, we’ve all had that experience where someone walks into a glass sliding door thinking it’s not there,” said Winkleman. “This is the inverse of that, and it was reasonable for Sam, the grandfather, to think that this was all glass because from his perspective, it was all glass.”

Winkleman says it’s possible Chloe herself may have opened the window.

Royal Caribbean International hasn’t responded to messages seeking comment.