LOS ANGELES, Jul. 14 – A jury is expected to be sworn in here today to try cultist Charles Manson and three young women of his nomadic “family” on charges of murdering actress Sharon Tate and six others in two bloody nights last summer.

After four weeks of questioning 141 prospective panelists it appears virtually certain the prosecution will accept the seven men and five women sitting in the jury box.

That possibly was supported by Los Angeles Superior Court Judge Charles H. Older’s decision in chambers yesterday morning to excuse the prospective jurors for the rest of the day and hear defense motions.

Manson’s attorney, Irving A. Kanarek, challenged the way the Los Angeles County Grand Jury is selected and questioned the method of selecting jury panelists for trials. Judge Older denied both motions, along with a move for a change of trial site sought by Ira Reiner, representing Leslie Van Houten.

Older’s rulings appeared to clear the way for co-prosecutors Aaron H. Stovitz and Vincent T. Bugliosi to accept the jury and for the beginning of the selection of six alternates, a process that may take a week.

Prospective jurors in the box range in age from William T. McBride, a chemical company reactor operator in his 20s, to Alva K. Dawson, a former sheriff’s deputy, who is 73.

The others are Mrs. Thelma S. McKenzie, secretarial supervisor in the Los Angeles County Department of Public Social Services; Mrs. Shirley Evans, secretary for the Los Angeles School District; Mrs. Jean Roseland, secretary for Trans World Airlines; Anlee Siston, an electrician; William Zamora, a technician for the California Division of Highways; Marie Mesmer, self-employed and a former drama critic; John M. Baer, an electrical tester; Mrs. Evelyn J. Hines, a dictaphone telephone operator for an insurance company; Walter B. Vietzelio, a retired plant guard, and Herman C. Tubick, a mortician.