A Sunset landlord murdered his tenant in an ambush outside the 58-year-old man’s home so he could sell the property without a renter in it, a wrongful death lawsuit filed Tuesday in San Francisco Superior Court alleges.

The complaint, brought by Dino Bigone on behalf of the estate of his father, Eric Bigone, accuses Phillipe Chagniot of shooting the elder Bigone with a silenced MAC-10 submachine gun after a monthslong campaign to force him out of a rental home in the city’s Sunset District. Chagniot’s wife, Barbara Chagniot, and the couple’s family trust are also named as defendants.

The allegations have not been proven in court, and the defendants have not yet responded to the lawsuit. Efforts to reach the Chagniots and their attorney were unsuccessful.

According to the complaint, Eric Bigone had rented the single-family home at 2518 47th Ave. since 2023, paying $3,200 in monthly rent in cash at the landlords’ insistence. The lawsuit claims the Chagniots demanded cash to avoid reporting the income on their taxes.

Beginning in January, the suit alleges, Phillipe Chagniot launched a harassment campaign aimed at pushing Bigone out so the property could be sold. The complaint says the landlords sent improper notices to enter, threatened eviction, refused to accept rent and falsely claimed they would invoke the Ellis Act, a state law that allows landlords to evict tenants when withdrawing a property from the rental market. Bigone hired an attorney simply to pay his rent, according to the filing.

When those efforts failed, the lawsuit alleges, the Chagniots conspired to kill him.

The complaint describes the killing in detail. At around 5 a.m. May 17, the lawsuit claims, Phillipe Chagniot dressed in dark clothing and a mask, rode a bicycle to the home armed with the gun, spray-painted nearby security cameras and set fire to Bigone’s car. When Bigone came outside to extinguish the blaze, the suit alleges, Chagniot shot him in the back of the head, then stood over him and fired again. Bigone was pronounced dead at the scene.

Chagniot, 68, was arrested May 27 and is being held without bail, according to the lawsuit. The San Francisco District Attorney’s Office has charged him with murder, arson, and several weapons offenses, including possession of a silencer and a large-capacity magazine, the complaint says.

The suit also alleges that the day after the killing, Barbara Chagniot called Dino Bigone to offer condolences and ask when he would vacate the home, and that Phillipe Chagniot sent a text message expressing sympathy. The complaint says that within days, the defendants’ attorney moved to take possession of the property.

The lawsuit raises 10 causes of action, including wrongful death, battery and violations of the city rent ordinance, which bars landlords from harassing tenants in bad faith. It also seeks to block the defendants from selling several properties they own in the city and elsewhere, arguing the transfers would be made to avoid paying any eventual judgment.

The plaintiff is represented by Paul Alaga and Ian Kelley of San Francisco’s Bryant Law Group. They are seeking general, punitive and other damages, along with injunctive relief, and have demanded a jury trial.