John Thomas (Bull) Ellis Jr., 44, a former construction worker and Capitol Hill aide, died at Capitol Hill Hospital Oct. 10 of head injuries received in an assault that D.C. police listed as a homicide.

Officials of the homicide squad said Mr. Ellis and another man got into an argument on E Street NE on Oct. 9 and that Mr. Ellis was knocked to the sidewalk, where he struck his head. They said a man had been arrested in the case, but declined to reveal his identity.

Mr. Ellis was born in Durham, N.C., and grew up in Washington. He graduated from Phelps Vocational High School and became a construction worker for various firms in the area. His family said he worked briefly on the staff of former Sen. James Abourezk (D-S.D.). When Abourezk retired from Congress in 1979, Mr. Ellis retired for reasons of health.

Survivors include his wife, Mary, and a son, John III, both of Washington; his father, John Sr., of Washington, and his mother, Lillie Ellis, and a brother, Larry, both of Syracuse, N.Y.; three sisters, Mary Evans and Johnine Rankin, both of Washington, and Jane Myles of Silver Spring; a grandmother, Elizabeth Cotton of Syracuse, and a grandchild.