The Private Investigators

 

There were a whole slew of private investigators doing work on the TLB case.

The Family Ed Sanders pg306
Mr. Peter Folger, Abigail Folger's father, according to numerous people involved, initiated an intense investigation into the matter, as did Roman Polanski who were assisted by several famous Los Angeles private investigators. ... In fact, at least ten private investigators in Los Angeles were used extensively throughout the investigation of the case, both by private parties and the district attorney.

newsblaze.com/entertainment/books/sharon-tate-a-life-by-ed-sanders-power-book-review_72226/
William Garretson’s attorney, Barry Tarlow, hired a private investigator to conduct an additional polygraph examination, hoping to get to the bottom of this survival mystery.

Here are some names:

labyrinth13.com/eBook-ROYF.pdf
Paul Krassner, writing for a 1999 edition of Scope magazine:
--When Hal Lipset, the renowned private investigator, informed me a few years ago that the Los Angeles Police Department seized pornographic films and videotapes found in Polanski's loft ,,,

--Excerpt from Sharon Tate - A Life by Ed Sanders
"Hatami told me he has no memory at all of Manson coming to the front door of Cielo Drive, but that the memory was suggested to him by an investigator named Reeve Whitson, who worked for both Col. Paul Tate and the prosecutor Vince Bugliosi."

[The Private Sector: Private Spies, Rent-a-Cops, and the Police Industrial Complex by George O'Toole c.1978 pg223

When the CIA first considered the very sensitive question of operating within the United States, someone must have pointed out that firms like Fidelity Reporting Service could offer ideal cover. Private detective agencies are licensed to snoop, and they provide a confidential service, routinely refusing to disclose their clients' identities. They could provide perfect camouflage for the CIA's domestic intelligence activities.]

--Ed Sanders and Paul Fitzgerald employed a private investigator(PI) named Larry Larsen.

--Scanlans, May 1970
"Michael McCowan was the investigator for the defense in the Panther case, as well as in the Charles Manson case..."

--Witness to Evil, by George Bishop c.1971  pg144
Hughes...employed an investigator, long-haired William Swinney, whose wife took to breast-feeding their infant baby while sitting on the floor of the corridor outside the courtroom, right beside the men's lavatories.

Did Leno have his own PI, hired to look into the break-ins at the Waverly house?

--www.mansonblog.com/2023/08/54-years-of-remembering-victims.html (comments section)
Louise(Leno's daughter) said...
As far as the burglaries, for example, I recall those instances on several occasions where Dad and Rose talked about them. They never had those issues on Woking Way. All happened at Waverly, there were many times it happened, and different things happened--rug cuttings once, moving things around, and the actual thefts/burglaries. Dad told us he hired a detective but I never saw him. All mysteries.

--truthontatelabianca.com/threads/maybe-something-new-maybe-not.5232/    poster 'martine'
What many do not know is that from very early on in their relationship, Peter Sr. had all of Gibbie's and Voytek's comings and goings monitored. Peter Sr. had an investigative and security team which could put the CIA and FBI to shame. In fact, both of these teams were made up of former members of these institutes and of the Secret Service as well as other high-ranking retired military men.

--Some details about PJ Tate's own private investigation:

Restless Souls, by Alisa Statman

pg73
PJ to Helder: "...I'm confident that my network of connections can accomplish in one day what will take your men a week."

pg74
PJ: I turned off the television. There were three other men in the family room, all friends from the US Department of Defense, all skilled investigators. After the murders, Guy was the first to offer his assistance. As an FBI agent, he'd spent twenty of his forty-nine years traveling the globe...
(The men start discussing plans to investigate Roman, One of the men--"Jake"--watches Roman being polygraphed by Lt. Deemer)

Thus 'Jake' is close enough to the LAPD to get access to the polygraph room.

Unfortunately whatever they found out is totally private and there has been no leaks(other than Larson) in the decades since.