Just happened to catch this partway through the first episode (Investigation Discovery channel). Looks like it originally aired on HBO, so is available on HBO Max as well. Gotta say, it's pretty interesting. If it hadn't been for "Starved Rock" in the title I probably would have passed it up. I had no idea this even occurred back in 1960, even though I've been to that area (Ottawa, La Salle, etc) many times. There's a good chance people here have stood where the murders happened, St. Louis Canyon, in the park itself.