Murder on the land 3229 pinkney st
Thanks for asking! I thought the question seemed familiar - I'm sorry to hear that you're still having unsettling experiences in the house. Not too much has changed from last July (answer below) but I took another look at the Historic Omaha World-Herald and a few other sources.
From 1913 to 1921, there was a retirement home down the street at 3029 Pinkney which would have collected its fair share of deaths from natural causes. Just west of the industrial lot, of course, there's a history of drama around the Malcolm X birthsite when Earl Little and family were driven from town. Adam Fletcher Sasse has a pretty good article on the Adams Park area. But I can't say any of that bears directly on your house.
I took a look in our Historic Omaha World-Herald archive (which you can search from home, too, with your library card) and a search for the address at 3229 Pinkney doesn't seem to turn up any stories of violent or unexpected deaths - certainly some interesting things have happened to folks who lived at the address: Prison breaks, car accidents, the occasional fire, but nothing particular about a death. Of course it could be that someone died in the home of natural causes, or a death may have gone unreported in the newspaper.
Houses can be noisy things...This article may help you track down other potential causes of the strange sounds that you're hearing.
And, as always, thanks for using AskOPL!