From 'Lost Lives' (entry 2326):

May 22, 1981 - Carol Ann Kelly (West Belfast, civilian, Catholic, 11, schoolgirl)
The schoolgirl was fatally injured by a plastic bullet fired by soldiers in disputed circumstances three days earlier. The round struck her on the head as she walked back to her home at Cherry Park, in Twinbrook, from nearby shops with a pint of milk. [...] The inquest found two plastic bullets had been fired from army Land Rovers. Soldiers said there was rioting in the area, but locals challenged their version of events and said it was quiet at the time. The coroner said the child was an innocent victim [...]. Her family was awarded 25,000 pounds in compensation. In 1993 a former member of the Light Infantry Regiment sent his Northern Ireland campaign medal to the schoolgirl's mother. The former soldier, Bob Harker, wrote a book on plastic bullets called 'A Harmless Way to Kill'. In May 1998, a new memorial stone to the girl was dedicated near her Twinbrook home after an existing memorial was targeted by vandals.

No mention of 'reprisals'. Might as well have been the result of a genuine mistake or a dare gone wrong. (Give a boy a weapon and he WILL try it out!) When they found they'd actually hit someone, and a child at that, they weren't mature enough to accept the responsibility. It's too scary to believe someone would take out his anger on an 11-year-old girl in cold blood!