Full Notification

Petaluma Police Department 
NEWS RELEASE
For Immediate Release
Friday, September 11, 2026

Subject Arrested after Arrest/Search Warrants Served
 
Incident Summary:
 
On Friday, July 24, 2026, at 11:54 pm, the Petaluma Police Department received a 9-1-1 call regarding a fight in progress on the 100 block of Eastside Circle. The reporting party indicated that two males were fighting and that one of the males was bleeding. When officers arrived at the residence, they observed blood in the driveway and entryway of the home but were advised the involved parties had already left. Occupants of the home advised the victim was one of the involved parties but were otherwise not cooperative with the investigation.
 
At approximately 12:39am, officers were dispatched to Petaluma Valley Hospital after being notified that a stab victim was brought in. Officers contacted the victim at the hospital who confirmed he was assaulted at the location of the initial call for service. The victim was transported to Santa Rosa Memorial Hospital for treatment. The victim received multiple injuries from the assault that were determined to be non-life threatening. Other than confirming the assault, the victim was also uncooperative. Petaluma police detectives were called to assume the investigation of an Assault with a Deadly Weapon (245(a)(1) P.C.).
 
Over the course of several weeks, detectives developed and followed up on several investigative leads. During the follow-up investigation, Michael Orsini (age 39, Penngrove) was identified as the assailant. Detectives authored search warrants for the location of the crime and Orsini’s residence. In addition, a felony arrest warrant was authored for Orsini’s arrest. Judges of the Superior Court of Sonoma County authorized the warrants.
 
On 9/7/26, deputies from the Sonoma County Sheriff’s Office developed information that Orsini was at his residence on the 200 block of Hatchery Road in Penngrove. This information was shared with PPD detectives. Based on the seriousness of the crime, it was determined that the SWAT team should be utilized in the service of said warrants at both locations.  
 
Later in the day, the Petaluma PD SWAT team secured the home where the assault took place. This included surrounding the home and ordering all occupants outside. Once secured, detectives served the search warrant for the residence, looking for evidence of the crime.
 
The PPD SWAT team then responded to Orsini’s residence. Officers again confirmed Orsini was home. SWAT personnel made several announcements regarding the warrants for Orsini and his residence but received no response. At approximately 8:27pm, crisis negotiators began speaking with Orsini via cell phone in an attempt to have him surrender peacefully. In addition to continual announcements from officers on scene, negotiators spoke with Orsini on and off for approximately three hours via phone. During the standoff, flameless CS gas was introduced into the house. At approximately 11:29pm, Orsini exited the house and surrendered. He was placed under arrest for his arrest warrant and transported to county jail after being medically cleared.
 
Pursuant to the search warrants, several pieces of evidence were located including cell phones, biological evidence, multiple knives, bear spray, a taser, and multiple firearms.
 
This is an active investigation. The Petaluma Police Department is asking community members that have direct knowledge of this incident to contact Detective Jacob Vedder at 707-781-1241 or via email at [email protected].
 
Media inquiries can be directed to Sergeant Ryan McGreevy at (707) 778-4415.