Sometimes people on probation break their rules. When this happens, their probation officer needs to be informed. A probation officer is actually easy to contact for these purposes.
Think about the consequences of reporting something to a probation officer. Is the information you have worth talking to a probation officer about? Will it waste the probation officer's time?
Find the location of the local probation office. It is probably listed in the phone book. If you can't find it there, Google "probation office" followed by the city.
Find a telephone number on the probation office's website to call the office or find an address if you want to see the person in the office.
Ask for the correct probation officer. If you know the name of the probation officer, then ask for him or her. If you don't know the probation officer's name, provide the name of your friend on probation and the office secretary can find the correct probation officer for you.
Share your information with the probation officer. Report legitimate concerns rather than making it a personal vendetta.
Listen to the probation officer and take whatever advice he or she gives to you. The probation officer has probably seen this situation before and knows how to deal with it.