A police investigator walks into a room. He sees two dead bodies on the floor, those of the unfortunate duo Alice and Bob, the players in many physics thought experiments. They had been locked in the room together. The investigator notices several things:

• The door was sealed, and remained sealed since Alice and Bob were locked in one day before.
• There is a broken window high up on the wall, with shattered pieces of glass all over the floor. The investigator finds that it is impossible to reach. The window was not broken when Alice and Bob were locked in. There are no other exits besides this window and the door.
• There is a table by the window approximately four feet in height. Even an unlucky fall wouldn't have killed a person.
• Security camera footage shows that nobody - living or dead - entered or exited the room. No inanimate objects entered or exited the room, either (obviously, things like light and air would have passed through the broken window). The footage is accurate.
• There is a glass on the table, which has also been broken. It appears that it was a glass of water, because water was spilled all over the floor.
• There is nothing else in the room - including no weapons.
• Alice and Bob's bodies appear unharmed. There are no traces of poison.
• Prior to being locked in the room, Alice and Bob had everything they needed to survive - food, water, oxygen, etc.
• Alice and Bob died before the investigator opened the door.

The investigator relates all this information to his supervisor. The supervisor cannot solve the puzzle, yet the investigator, smiling, says that he knows the answer.

How did Alice and Bob die?

^{Note: This isn't a riddle of my own devising. A friend of mine got it from somewhere, and related it to me.}