You are right. I posted an account of the trial at the anniversary of the murder - August 29, 1857 - but the trial wasn’t until the next year. I never realized that.
I read this book a few years ago, it has the Lincoln picture on the cover.
https://www.amazon.com/Moonlight-Abraham-Lincoln-Almanac-Trial/dp/0312229224
“Moonlight: Abraham Lincoln and the Almanac Trial”
http://www.mrlincolnandfriends.org/the-women/hannah-armstrong/
“”Mr. Lincoln wrote “Aunt Hannah” in September 1857: “I have just heard of your deep afliction, and the arrest of your son for murder. I can hardly believe he can be capable of the crime alleged against him. It does not seem possible. I am anxious that he should be given a fair trial at any rate; and gratitude for your long-continued kindness to me in adverse circumstances prompts me to offer my humble services gratuitously in his behalf. It will afford me an opportunity to requite, in a small degree, the favors I received at your hand, and that of your lamented husband, when your roof afforded me a grateful shelter, without money and without price.”””