Individual Details

I believe that Clara Melville that married John Gilbert Casey and Vada Melville that married his brother Columbus were sisters.
1920 Census. Justice Prec. 4, Fannin Co, TX, Hh 94
Jim A. Melville, age 49, b. Arkansas, father b. Ireland, mother b. SC, farmer
Annie S., wife, age 45, b. AR, father b. AR, mother b. TN
Vada M., dau, age 15, b. TX
Emma M., dau, age 10, b. TX
Clara B., dau, age 7, b. TX

Their father took his own life.
Found on FindAGrave.com
James Andrew Melville
Birth: Feb. 23, 1869
Arkansas, USA
Death: Feb. 22, 1941
Greenville, Hunt County, Texas
Newspaper Article image posted:
James A. Melville Found Dead Here, With Gun Nearby
James Andrew Melville, who was to have celebrated his 72nd birthday Sunday, was found dead about 7:30 o'clock this morning by D. P. Tabor, 1518 Walworth Street, in whose home he boarded. A bulled had pierced Mr. Melville's chest and a .22 pistol lay on the floor nearby. Justice of the Peace, E. W. Hagan, rendered a verdict of suicide.
Mr. Tabor, unable to awaken Mr. Melville for breakfast, stated that he broke into the locked room of his boarder to find Mr. Melville dead. The elderly man had been boarding at the Tabors since October.
Funeral arrangements had not been completed today but probably will be held in Ladonia Sunday. A daughter, Mrs. John Casey of Ladonia, was preparing a birthday dinner in Mr. Melville's honor.
Born February 23, 1869 in Arkansas, Mr. Melville came to Texas about 30 years ago, and had made his home in Greenville for more than 10 years. He was a retired carpenter and farmer. His wife preceded him in death a number of years ago.
Mr. Melville regularly attended the Henry St. Church of Christ in this city.
Surviving are six children: Clyde & Audie Melville of Greenville.; Ernest Melville, Enid, Okla.; Mrs. C. D. Casey and Mrs. John Casey of Ladonia, and Mrs. E. D. Holly of Emory.

Texas Death Certificate #8716
James A. Melville died Greenville, Hunt Co, TX, at 1518 Walworth St. He was born 25 Feb 1870 and was a retired farmer, widowed. Father was Elxander [sic] Melville, b. Arkansas; mother's name unknown. He died 22 Feb 1941 of suicided by a .22 target rifle. Informant was Clyde Melville of Greenville. The body was removed to Ladonia for burial.

Birth	1905	Texas
Marriage		Columbus D. Casey Jr.

Spouse	Columbus D. Casey Jr. (1894 - 1970)
Child	Helen Melville Casey ( - )
Child	William Charles Casey (1929 - )

Father	James Andrew Melville (1869 - 1941)
Mother	Annie S. [Melville] (1875 - )
Sibling	Clara Melville (1913 - )