Fortunately, they don't happen often. As I said earlier, the Correctional Service released a report that I signed. On average, just over eight inmates a year commit murder while on parole in the community.
I've given some examples, and you can look up the information in the archives. I calculated that 83 murderers reoffended over a 10-year period. Of those 83 inmates, 10 had already committed a murder while on supervised release. So there have been 10 cases comparable to Mr. Gallese's case in 10 years. That's one case per year. This isn't very rare.