She witnessed the murder of Jenkins but did not see the murderer. Correctly assuming that she would be accused of the crime, she disguised herself as a robot waitress and asked for River Song's help. When the real murderer, Marcus Gifford, tried to kill River and Isabella Clerkwell by shutting off oxygen in the room with them, Spritz opened the door, saving their lives.
Although River herself believed Spritz, she could not hope to persuade the Rulers of her innocence. Instead, River made the Rulers believe that Spritz was dead and put her on a shuttle, free to see the universe. (AUDIO: I Went to a Marvellous Party)