The MAIB (the maritime transport safety investigation board of the UK) has recently published a safety bulletin about liferafts that weren't properly serviced by a service station.
The full report is available here. In short, what happened was that a fishing vessel sank. When the crew attempted to deploy one of their liferafts, it didn't properly inflate. Luckily, they had a second liferaft that did inflate, but it was later found that it was also not properly serviced and contained batteries, flares, emergency kits and supplies that were beyond their due date by at least 10 years.
The MAIB's task is to prevent the recurring of such events, so they made a recommendation to have all liferafts re-serviced that were "done" by said service station. Investigations also showed that this wasn't a one-time problem, but several life rafts serviced by that station had similar issues and this must have been going on like this for years (the rafts were serviced yearly by the same service station).
Being a sailor myself, this is shocking, and I do hope that someone so carelessly and deliberately putting people's life at stake will face severe consequences. However, the MAIB report (as all of them do) contains the sentence
This bulletin is not written with litigation in mind and, pursuant to Regulation 14(14) of the Merchant Shipping (Accident Reporting and Investigation) Regulations 2012, shall not be admissible in any judicial proceedings whose purpose, or one of whose purposes, is to apportion liability or blame.
On the other hand, this agreement clearly indicates that the MAIB may share evidence with the police, but it's unclear to me how that works in practice.
How can a prosecutor open an incident and present the evidence, without the defendant just arguing that the evidence was presented in the MAIB report and hence is inadmissible in court? Based on this other question I'm assuming that a possible charge will be serious (the customer has no way of checking whether a life raft was serviced properly - he just gets back a sealed container that is only to be used in case of dire need).
[This particular incident happened to a UK vessel, the service station was in Spain, but since the transport safety investigation committees in most countries work similar, jurisdiction is probably not so important here]