LOS ANGELES, Dec. 10 – Members of “the Manson Family” hippie cult who turned informers and “grinding day and night work” broke the Sharon Tate murder case, says the chief police investigator of the brutal crimes.

The timetable for the investigation of the bizarre killings was disclosed by Police Capt. Hugh Brown, robbery-homicide division commander of the police department.

More than 40 investigators were assigned to the Tate case and the slayings of Leno LaBianca and his wife. The four-month investigation included the probing of 150 murders in southern California in the past year, according to Brown.

Chronological events of the case were:

Aug. 9 — Sharon Tate and four other persons slain in her rented Benedict Canyon estate.

Aug. 10 — LaBianca and his wife Rosemary killed, first attributed to a “copycat” assailant because of gruesome similarities.

Oct. 15 — Police became aware of similarities between Tate-LaBianca murders and slaying of musician Gary Hinman, 34, last July.

Oct. 20 — Sheriff’s detectives handling Hinman case inform police they have learned of a girl who might have information about a roving band of hippies who may be involved in the slayings.

Oct. 31 — Girl interviewed. The name of Charles M. Manson, leader of the cult implicated in slayings. It was the first mention of Manson.

Nov. 1 — Detectives contact Manson’s parole officer, and obtain more information about “the Manson Family.”

Nov. 12 — A major break. Police in suburban Venice reported a suspected burglar in jail might have more information on the suspects. Informant interviewed the same day and provides name of another possible informant.

Nov. 13 — Second informant located and tells of overhearing talk that some members of band might be implicated in slayings.

Nov. 18 — Beverly Hills police report a woman suspect in another case disclosed conversations with Susan Atkins, a member of the cult and cellmate of the woman.

Nov. 26 — Final break. Former cellmate relates to police the girl’s story about Manson and his followers. Miss Atkins was questioned and reveals the details of the slayings.