How to write a better murder scene

I'm writing a memoir and I'm including a scene where my grandmother was murdered (50 years ago, well before I was born).

I just reread what I wrote and I'm not quite satisfied with it. I feel like the pacing might be too fast or something. But it's hard to stretch it out because I'm relying on outside information as I wasn't there. I made a concerted effort to show not tell, none-the-less, making it sort of a play-by-play instead of simply giving a 2nd/3rd-hand account. I gave myself a little wiggle room to embellish and add details (e.g. they were hiding in the bedroom and they prayed silently...I don't know if they were praying, but it's minor).

It's hard for me to tell if there's suspense since I already know what happens, but I try to keep the reader guessing in how I reveal the event, creating points where things could go one way or another. I also try to include backstory about my grandmother so the reader can establish some sense of connection with her, but it's hard since I just don't have a ton of information on her and I feel like the details I do include about her come off a little dry and generic.

My purpose for including the event is because it shape my mother and our relationship and there are other events in the future that are important to my main story where the murder is referenced.

One thing I'm debating is how I should refer to my grandma: as "Grandma", "my mother's mother" (to emphasize how it influenced my mom specifically), or by her name. I'm leaning against "Grandma" since she wan't a grandma yet when she died and I never met her and I sort of want to remove myself from the scene and not have it be about me.

I do a little POV jumping I think. I reveal events from the my relatives POV at times while other times from the gunmen's POV. I think it's works though and is good for creating suspense.

Any ideas how to make the scene more compelling?

Thanks for the feedback.

Disregard what I said about jumping POV's.

Yes, details are important, and I have a limited supply of them. I'm doubtful I will be able to find newspapers or other hard documents as this happened decades ago and in a small village in a foreign country.

I see what you mean about how this delves into a different genre from memoir. I guess I just went astray because I was trying really hard to "show not tell."

This part of the book is very brief in the grand scheme of things and the rest of it very much is a "proper" memoir. I guess I just thought the readers would establish more of a emotional connection/attachment to my mother, who is a main character in my memoir, by revealing this backstory in the form of a scene rather than simply stating it as an aside/simple fact.

Anyway, I probably am getting ahead of myself. That was my first attempt at writing it as a scene, and I just felt like the pacing of it was too abrupt (as a result of limited details and info). But I'm sure eventually after I let it sit for a while I will resolve how I should best include this event.