Chiari v. City of San Mateo
- Maxine Chesney
- 3:24-cv-06780
- U.S. District Court · Northern District of California
- 4
In Stephen Chiari v. City of San Mateo, Judge Chesney denied leave to add a fabrication-of-evidence claim because Chiari missed the amendment deadline without diligence.
Stephen Chiari's request to add a deliberate-fabrication-of-evidence claim against Officer Leroy Becker was denied; the opinion also addresses defendants City of San Mateo and Officer Becker, who opposed the motion.
What happened
In Stephen Chiari v. City of San Mateo, Stephen Chiari brought federal and state claims arising from his 2018 arrest and later criminal prosecution, which ended in his acquittal.
Chiari asked to add a federal civil-rights claim accusing Officer Leroy Becker of deliberately fabricating evidence. He relied on the same facts already alleged in his complaint, rather than new facts discovered after the deadline to amend pleadings.
Judge Maxine M. Chesney denied the motion because Chiari did not show the required diligence for extending the deadline. The judge also vacated the scheduled hearing.
The detailed version
- Chiari v. City of San Mateo · No. 3:24-cv-06780
- Maxine Chesney
- Nov. 3, 2025
Background
Stephen Chiari asserted federal and state claims arising from his 2018 arrest by Officer Leroy Becker on a felony charge involving operation of a boat under the influence and causing injury. In 2019, the San Mateo District Attorney's Office filed misdemeanor charges for reckless operation of a boat and operating a boat while impaired. A jury acquitted Chiari of all charges.
One of the six causes of action in the complaint was a claim under 42 U.S.C. § 1983 for malicious prosecution against Becker. Chiari alleged that Becker acted out of personal animus and that the charges were based primarily on false statements in Becker's police report.
Motion to Amend
Chiari moved for leave to file a first amended complaint adding a § 1983 claim for deliberate fabrication of evidence against Becker. The proposed claim alleged that Becker deliberately fabricated evidence used to criminally charge and prosecute Chiari.
The court explained that Federal Rule of Civil Procedure 15 generally calls for freely allowing amendments when justice requires. But because the court's scheduling order set April 10, 2025, as the deadline for amending pleadings, Rule 16 required Chiari first to show good cause for extending that deadline. Good cause requires showing that the deadline could not reasonably be met despite diligence. Only if good cause is shown does the court then consider whether amendment is proper under Rule 15.
Court's Analysis
Chiari's counsel stated that, after deposing the deputy district attorney who tried the criminal case, counsel determined that possible defenses could apply to the malicious-prosecution claim, including probable cause and the presumption of prosecutorial independence. Counsel stated that those defenses would not apply to a deliberate-fabrication claim.
The court noted that Chiari did not claim to have learned any new facts supporting either required element of a deliberate-fabrication claim after the amendment deadline. Those elements are that the defendant deliberately fabricated evidence and that the fabrication caused the plaintiff's loss of liberty. Instead, Chiari acknowledged that the proposed claim relied on the same facts already alleged in the complaint and had already been used to support the malicious-prosecution claim.
The court therefore found that Chiari had not been diligent in seeking to pursue the proposed claim. The court stated that whether the defendants would be prejudiced was not relevant to the diligence question. Although prejudice could provide an additional reason to deny a scheduling-order modification, the court focused on Chiari's reasons for seeking the modification and ended its inquiry after finding a lack of diligence.
Disposition
The court denied Chiari's motion to amend. It also vacated the hearing scheduled for November 7, 2025.
Read the full 4-page opinion on CourtListener, the free public archive maintained by the Free Law Project.