General Casteel was murdered by being shot, clubbed and stabbed by the lover of his wife Betty Cash. The murderer and Mrs. Casteel were charged with first degree murder. She was acquitted. He went to the electric chair. I have Newspaper articles online with ancestry.com concerning this matter
Contributor: Crystal Burnham (46590834) •
The following information provided by Find A Grave member 47239320 casteelroots (06/09/2022):

James Gentile M. "General" Casteel has been referred to by name in various ways. On the 1900 US Census taken at Civil Dist. 13, McMinn Co TN where he is living in the household of his parents he is recorded as being GENERAL M. CASTEEL. The persons in the household listed by name are his parents – Jasper and Mary E. Casteel; and SIBLINGS – John W. Casteel, JAMES A. CASTEEL, Cornilus (Cornelius) Casteel, and Cora L. Casteel. . On his McMinn Co TN Marriage Record to wife, Bettie Cash on 18 May 1904 he is recorded as G. M. Casteel (transcribed as Castell at Ancestry.com). On the 1910 US Census taken at Civil Dist. 3, McMinn Co TN he is listed with his wife, Bettie and 3 children and is recorded as Gennral (General) M. Casteel. On the 1920 US Census taken at Armuchee, Floyd Co Georgia he is recorded as General Casteel. On the 1930 US Census taken at Bridge Creek, Colquitt Co Georgia he is recorded as James M. Casteel for the 1st time. On his Florida Death Certificate he is named as GENERAL CASTEEL. His daughter Mary Casteel Robinson was the informant on his Florida Death Certificate. Newspaper accounts of his murder list him as J. M. Casteel or J. L. Casteel.

There are 2 daughters that are not attached to Mr. Casteel's Find A Grave Memorial. Those daughters are – Ruby Casteel and Alma Casteel.

Ruby was born circa 1927 in Florida according to her 1930 US Census where she is in the household of her parents and siblings at Bridge Creek, Colquitt Co Georgia. Ruby is again listed after the murder of her father in a Florida state run children's facility on the 1935 Florida State Census taken at Precinct 10, Duval Co Florida with her siblings – Horace and Della Casteel. After this she drops from the record under the surname of Casteel. She was probably adopted and assumed another name. She is not mentioned in newspaper articles regarding her father's death nor in any of her sibling's obituaries.

Mr. Casteel's youngest child, Alma Casteel was born 2 Aug 1931 in Florida. She and Ruby are spoken of in the 15 Feb 1934 Orlando Sentinel Newspaper article regarding the murder of their father. Alma was adopted by Earl and Edna Pearl (Cason) Morris, and she became Amalee Morris. Amalee married 1st Edwin Estey and 2nd Dale Karnes. She is referred to in her sister Alice Casteel Reyes' 1999 obituary as "Amerlee of Pensacola" and in the 2001 obituary of her brother Horace as "Amalee Estey, Fort Walton Beach." Alma Casteel adopted as Amalee Morris died on 01 Sep 2007 in Fort Walton Beach, Florida. Her 2007 obituary as published in the Palatka Daily News (Palatka, FL) lists her as Amalee Morris Karnes with her Estey children as survivors.