LOS ANGELES, Apr. 8 — A Superior Court judge today had denied defense motions to hold separate trials for Manson cult members accused in the Hinman-Shea murder cases.

Judge Raymond Choate ruled that Charles Manson 36, Susan Atkins 22, Bruce Davis 27 and Stephen Grogan 19 will be tried together on May 20 in connection with the crimes.

Manson and Davis each are charged with both slayings. Miss Atkins is accused of the Hinman murder, while Grogan is charged in the Shea slaying.

Musician Gary Hinman was killed July 27, 1969, in his Topanga Canyon home. Donald “Shorty” Shea allegedly was murdered sometime between August and September 1969, but his body has never been found.

Attorneys for Manson and Miss Atkins entered “once in jeopardy” pleas to the Hinman murder and to a count of conspiracy involving the slaying. Such a plea is rare.

Their attorneys claimed each defendant already has been placed in jeopardy because Superior Judge Charles H. Older, who presided over the Tate-LaBianca murder trial, had given that jury instructions concerning the Hinman murder.

Miss Atkins, during the Tate-LaBianca trial, took the witness stand and admitted slaying Hinman.

Manson and Miss Atkins, and two other young women, have been condemned to death for the Tate-LaBianca murders.

Judge Choate will rule April 13 on whether Manson and Miss Atkins actually will be allowed to plead “once in jeopardy.”

If he allows the pleas to stand, defense attorneys have asked for a jury trial on whether, in fact, the two defendants have actually been placed in jeopardy.

Judge Choate set April 16 for all other pre-trial motions. In addition, the judge entered pleas of innocent for Manson and Miss Atkins on the two Hinman charges.

Manson’s attorney, Irving A Kanarek, entered a plea of innocent for his client to the Shea murder.

Davis pleaded innocent to all counts. Grogan already has entered a plea of innocent to the Shea murder.