Police asking motivation for reporting crime.

Did they accept your reasons? I assume you felt it was dangerous, offensive, bullying etc. but was it a crime?

The police don't usually become involved in something which isn't crime-related.

Message withdrawn at poster's request.

I didn't report it to police, i alerted the subject's office.

Have I got this right ?
You reported to somebody s office superiors that they were writing threatening things on social media Presumably the office superiors were worried enough to take it to the police who then contacted you to know your motivations for the original report ?
Well I expect the police get many reports that are maliciously created so need to be sure that reports like this are not just made up so it sounds a normal procedure to me

Are you in touch with the other people that reported it, you say there were others, and have they been seen by the police the same as you ?

You became part of a police investigation - Asking what your motivation was for reporting the post was part of the investigation -- not unusual - It can be difficult to discern what posts are technically considered threats - Personally, I think it's best to err on the side of caution and report - Users get away with saying a lot on FB by not saying things directly but by being cryptic and suggestive -

My take on it is that the OP notified the office of the person who was the subject (not the writer) of the threats in the social media post.

If you are the subject of an article you are not the writer/author (in this case) you are the person being written about.
Why would anyone think otherwise?

Police would want to know what interest you had in the offending article or if you knew the author or the subject.
It's a bit like GN.
People objecting to something not written about or specifically to them. Upping cudgels on behalf of but not instigated by, someone else.

I alerted someone to a social media post about them that was threatening to divulge personal information to hostile parties and accompanied by visual information that showed their home location. I thought it should be removed, they presumably reported it to police who then contacted me as part of an investigation.

I was just concerned because it seemed strange, like asking why i rang to say the corner shop was robbed rather than looking at the finger prints at the scene IYSWIM. I have no worries if it is regular procedure.

Sounds normal procedure to me I presume they would contact you if you reported a burglary at a corner shop as well as going to check the shop
All the services get so many hoax calls

Do you know the person whose post you reported?
Do they know you?
If not, I can't see what you are worried about.

DammitJanet I take your point and think it very strange too

I am very scared of the person who made the post and they are personally known to me, the chances of them finding out are high.

I would not have done anything if i had known that others were reporting it as well but i felt it was the right thing to do at the time and was and still am genuinely concerned for their target's safety.

It seemed a weird way to go on when all they have to do is look at a post and photograph, it's pretty black and white to me.

Thank you Anja.

I’d say you need to ask to speak to whosoever is in charge of this case and tell them your fears and worries.

Thank you Anja but from what i can make out it was the person in charge who contacted me (not a constable).

I did check that it was a legitimate officer via 101 because they contacted me by email but i don't think i checked whether the case itself was.

I have reported 2 robberies via 999 and police took my details including name, address, mobile and landline numbers and email address.
I was, later that week, contacted by a named officer who asked if I would be willing to give a written statement and, if needed, appear as a witness.
It's all normal procedure.

The only questions i was asked were how i saw the post (it was public) and why i reported it to the target and the social media site.

I'm not a witness and they said they won't be contacting me again

Seemed odd questions to ask, the police contacted me out of the blue, i had not reported this to them and it has made me a bit nervous.

I can see what you mean. You are not certain that the person who emailed/spoke to you was who they said they were and are worried that the perpetrator of the post may be trying to find out who reported it and may try to to exact some revenge.

If I ave interpreted your conscerns corrrectly, I too would be worried. I would have thought it worth your while to speak to the police and see if someone in authority can explain their enquiry and the way they did it.

Oh, and give you an opportunity to express your fears.

Thank you @M0nica, I rang and was told there should be a reference number on the email and there isn't, they ran the names through and there does not appear to be any investigation. I am waiting for the police officer to ring back or drop an email with this number but he does not seem to be in a hurry.

I would chase them up. What has happened is worrying and threatening an dthey should take action. Take a family member or friend with you when you next see the police so that you have a witness and someone who can helo you tell your tale.

I got a reply that makes even less sense quoting the GDPR as a reason to not give me any reference number but the names of both parties are bandied about well enough :/ and I was directed to the office of the person who (allegedly) complained to the police for validation when I expected an official police route.

Is it me?

This sounds weird. Contact your area Police Commissioner or MP. You could also take it up with the office of the Data Commissioner.