San Francisco prosecutors have revealed a shocking murder plot allegedly hatched by a wealthy landlord determined to get rid of his longtime tenant — by any means necessary.

Retired dentist Phillippe Chagniot, who ran his family’s rental property in the sleepy Sunset beach neighborhood of San Francisco, was allegedly desperate to sell the $1.3 million single-family home and resorted to horrifying measures to get the property vacant, allegedly orchestrating an elaborate ambush plot before before murdering his 58-year-old tenant, Eric Bigone, in an early-morning execution.

A neighborhood source told The Post that Bigone and Chagniot had “beefed” in recent months over a potential buyout package — as local tenants’ laws require landlords to offer money to tenants, sometimes totaling tens of thousands of dollars, in many eviction cases.

Bigone reportedly “knew his rights” and had lawyered up to hash out an exit package.

Records show the 944-square-foot home, owned by a trust tied to Chagniot’s wife, skyrocketed in value to $1.3 million in the red-hot San Francisco real estate market, where tiny homes in the residential beach district regularly sell for well over $1 million.

Rental filings with the city show a property matching the cozy home’s description fetching more than $3250 in monthly rent.

Chagniot — a familiar name in the community who ran a dental practice and sent children to exclusive St. Ignatius College Prep — had reportedly “lost it” over his wife’s cancer diagnosis before allegedly donning a mask to murder his tenant just after 5 AM on May 17.

The unhinged ex-dentist then allegedly donned “dark clothing and a mask” and spray-painted various surveillance cameras in the area to try to evade detection, prosecutors said, before approaching the residence at 2518 46th Ave.

Chagniot allegedly lit a fire “on top of a car” in front of Bigone’s home as he was getting ready for his job at the Public Utilities Commission, where he earned roughly $130,000 per year as a general laborer, in an attempt to lure him outside.

Chagniot then “hid off to the side,” per prosecutors, before shooting Bigone in the back of the head with a “silenced and fully automatic Mac-10” gun.

He then “casually” biked away, according to the San Francisco District Attorney’s Office.

Chagniot was nabbed in the alleged murder with the help of Flock Safety cameras in the area, which cops used to identify his bicycle and vehicle and track his movements.

Surveillance photos obtained by The Post show a thin figure in disguise stalking the quiet street with a long gun.

Curiously, Chagniot was involved in a separate murder case in 2006 that resulted in the conviction of Joseph Cua, a San Mateo Man, in the murder of an elderly couple whose property he managed. Cua, who has maintained his innocence, claimed in a California Court of Appeal petition that Chagniot provided false testimony during the trial.

“He was such a giving person. Even when I was sick, he came to my house every single weekend — sometimes spending the night just to make sure I was okay,” Bigone’s mother said at a recent memorial led by the Archdiocese of San Francisco.

“He was a wonderful father and a wonderful grandfather. He loved his family deeply, and they loved him.”

Chagniot is facing murder, lying in wait, arson, and gun charges.