New surveillance video shown to CBS News reveals the final moments before an 18-month-old girl fell to her death off a Royal Caribbean cruise ship. Chloe Wiegand was being held by her grandfather Salvatore Anello while the ship was docked in Puerto Rico in July.

Prosecutors have charged Anello with negligent homicide. He appeared in court Wednesday and was expected back in court on Dec. 17.

The video, which has not been released publicly, will be a key piece of evidence in the criminal trial, CBS News correspondent David Begnaud reports. The video shows what appears to be 18-month-old Chloe cross over to the side of the ship and stand in front of a bank of windows. A man attorneys said is Anello is seen following her.

There was a railing about a foot from the windows, Michael Winkleman, the Wiegand family's attorney said. The surveillance video appears to show Anello look over the railing for one second.

He then reaches down, picks Chloe up and appears to hold her over the railing. Winkleman said Anello didn't realize there was no glass directly in front of him. Within five seconds Chloe falls more than 100 feet below.

"She's sitting on the wooden banister, why did he then lean forward with her?" Begnaud asked Winkleman.

"I think it's pretty obvious why they leaned forward, and that would be so that you could get a better view," Winkleman said.

"What do you say to the fact that he raised her and put her on this banister which the cruise line might argue was not meant for young children to be sitting on?" Begnaud asked.

"If that was the case and they want no one to sit on it, they should say no one should sit on it. … There's no sign that says that. There's no warning, no nothing," Winkleman said.

"It may be hard for some people to believe that the grandpa didn't know that that section of the window was open. … How did he know that there was glass?" Begnaud asked.

"The only way that you can prove or disprove anything that Sam said is based on the video and based on his testimony … Those are the only pieces of evidence you have," Winkleman said. "There were no eye witnesses. There's no one who's come forward to tell any different story. … So all you have is Sam's testimony, his story and the video."

After Chloe fell out of the window, Anello drops to his knees, according to Winkleman, and he yelled out loud, "I just dropped my child. I thought there was glass! I thought there was glass!"

Royal Caribbean did not immediately respond to a request for comment.