SAN QUENTIN, Ca., Jun. 12 – Convicted killer Charles Manson has been quietly transferred from Folsom Prison to San Quentin for his own protection, officials said.

The transfer took place Friday but was not disclosed until this week.

Manson, who has been at the Folsom facility near Sacramento for 2 ½ years, was assaulted by two inmates in the prison yard May 3. Officials said Manson needed tighter security and the transfer was arranged.

Manson was convicted of the 1969 slayings of actress Sharon Tate and six others. He is serving a life sentence.