Prosecutors allege Chagniot carried out what investigators have described as an ambush killing. According to reporting by Mission Local, the case centers on a dispute over relocation payments — the compensation San Francisco law requires landlords to provide tenants who are displaced so an owner can sell or reclaim a property.

Chagniot, a retired dentist, was arrested in connection with Bigone's death. The arson charge suggests investigators believe the alleged attack involved more than a single act of violence, though the full charging details have not been made public.

The case drew early confusion. Initial surveillance images released by police showed a figure on a bicycle that community members and online observers said did not appear to match a man in his late sixties. That disconnect fueled speculation in the days before Chagniot's arrest, with some social media accounts raising the possibility of a third party. Those questions remain unresolved in the public record.

Bigone's background received scrutiny in early coverage, with some outlets noting prior legal history. That framing has since given way to the picture investigators presented at arrest: a landlord-tenant dispute over a legally mandated payment, allegedly ending in a tenant's death.

Relocation assistance requirements under San Francisco's Rent Ordinance can run to tens of thousands of dollars depending on unit size, tenure, and household composition. The DA's office has not publicly stated a specific dollar amount tied to the alleged dispute.

Chagniot's arraignment is the first procedural step in what is likely to be a lengthy case. Watch for a preliminary hearing date, where prosecutors will be required to present evidence sufficient to hold Chagniot for trial.