When a Sesslin affidavit is filed in a California case, a peace officer has submitted a sworn written statement of facts to a magistrate asking the court to issue an arrest warrant for a named person. The name comes from the California Supreme Court’s 1968 decision in People v. Sesslin, which held that an arrest warrant is invalid unless the complaint or supporting affidavit gives the judge actual facts to evaluate, not just an officer’s “information and belief.” If the affidavit is legally sufficient and the magistrate signs the warrant, the person named can be arrested; if it is not, the arrest is unlawful and evidence that flowed from it can be suppressed.1vLex. People v. Sesslin
What the Affidavit Has to Show
A Sesslin affidavit must give the magistrate enough factual detail to make an independent probable cause determination. Two categories of information are required:
- Facts indicating the specific crime was committed by the specific person named, not a recital of the statutory elements of the offense.
- Facts establishing the reliability of the information and the credibility of its source. If the officer is relying on tips, witnesses, or records rather than personal observation, the affidavit has to explain why those sources should be trusted.2Stanford Law School. People v. Sesslin
The judge cannot simply accept the officer’s conclusion that a crime occurred. The magistrate has to personally weigh whether the facts presented add up to probable cause. An affidavit built on boilerplate language or legal conclusions will not support a valid warrant, and any evidence obtained through the resulting arrest is vulnerable to suppression.1vLex. People v. Sesslin
Where the Requirement Comes From
Gerald Sesslin was charged in 1966 with multiple counts of forgery and grand theft. An officer signed a nine-page felony complaint, and a municipal court judge issued the arrest warrant based on it. After the arrest, Sesslin was required to provide handwriting exemplars, which prosecutors used to link him to a $5,800 forged check. He was convicted of one count of forgery.1vLex. People v. Sesslin
The California Supreme Court reversed on April 10, 1968. The complaint stated only the officer’s “information and belief” and echoed the statutory language of the charged offense without laying out any actual facts. It did not identify the officer’s sources, give any basis for believing those sources were reliable, or connect Sesslin to the alleged crimes through specific allegations. Simply listing “Witnesses” at the end of the complaint was not enough. Because the warrant was invalid, the arrest was illegal, and the handwriting exemplars taken after the arrest were “fruit of the poisonous tree” and should never have been admitted at trial.2Stanford Law School. People v. Sesslin
That ruling is the floor every California arrest warrant affidavit has to clear.
Who Files It and How
Under California Penal Code Section 817, a peace officer prepares the sworn declaration of probable cause supporting the warrant. The declaration must be a written statement signed under penalty of perjury, though it can also be submitted orally under oath if recorded, transcribed, and certified by the magistrate, or by fax, email, or computer server with digital signatures. The officer closest to the facts usually drafts the document, sometimes with input from the district attorney’s office. The magistrate reviews it and, if satisfied that probable cause exists, signs the warrant.3California Legislative Information. Penal Code Section 817
Once the warrant is served and the defendant is in custody, the arresting agency files a certificate of service with the clerk of the issuing court. The certificate records the date and time of service, the defendant’s name, the location of the arrest, and the place of incarceration.4FindLaw. California Penal Code Section 817
What Happens After the Affidavit Is Filed
With a signed warrant in hand, law enforcement can arrest the person named and take them into custody. The first court appearance after arrest is the arraignment. At that hearing, the judge informs the defendant of the charges, advises them of their constitutional rights, and asks for a plea.5California Courts Self Help. Arraignment
The judge also decides custody status. The defendant may be released on their own recognizance, released with conditions such as electronic monitoring, held on monetary bail, or held without bail. The judge weighs the seriousness of the charge, public safety, and the risk the defendant will fail to appear.5California Courts Self Help. Arraignment
If the defendant has not yet appeared before a judge, bail is set at the amount specified in the warrant. When the warrant does not specify an amount, bail defaults to the uniform countywide schedule adopted annually by the superior court judges of that county under Penal Code Section 1269b. For felonies, the schedule must account for aggravating factors such as violent felony enhancements. After the first appearance, the judicial officer can set bail above or below the schedule amount.6FindLaw. California Penal Code Section 1269b
In felony cases, the defendant has a right to a preliminary hearing within 10 court days of the arraignment. That period can be extended to 60 days if the defendant waives time or the court finds good cause. In misdemeanors, trial must start within 30 days of the arraignment if the defendant is in custody, or 45 days if not.5California Courts Self Help. Arraignment
How to Challenge the Affidavit
A defendant who believes the affidavit was legally insufficient or dishonest has several overlapping tools. Defense attorneys often file more than one at the same time.
Motion to Suppress Under Penal Code 1538.5
The primary statutory tool is a motion to suppress evidence under Penal Code Section 1538.5. The defendant argues that the warrant was “insufficient on its face” or that “there was not probable cause for the issuance of the warrant.” The motion must be in writing with a memorandum identifying the specific evidence to be suppressed and the factual and legal grounds for the challenge. If granted, evidence obtained through the unlawful arrest cannot be used against the defendant at trial.7FindLaw. California Penal Code Section 1538.5
Motion to Quash and Motion to Traverse
A motion to quash attacks the legal sufficiency of the affidavit on its face, arguing that the facts as stated, even if true, fall short of probable cause. A motion to traverse goes further, challenging whether the facts in the affidavit are actually true. The two are commonly paired with a 1538.5 motion to cover both angles at once.
Franks Hearing
If the defense has evidence that the affidavit contained deliberate falsehoods or was written with reckless disregard for the truth, it can request a Franks hearing, named for the U.S. Supreme Court’s 1978 decision in Franks v. Delaware. To earn the hearing, the defense must make a preliminary showing of three things: that the affidavit contained specific false statements or material omissions, that the officer knew they were false or acted recklessly, and that the false information was material to the magistrate’s probable cause finding. If the judge holds the hearing and finds the warrant rested on materially false or misleading information, the warrant is invalidated and the resulting evidence can be suppressed.7FindLaw. California Penal Code Section 1538.5
Sesslin Affidavit Versus Ramey Warrant
These two often get mixed up in California practice, and the distinction matters if you are trying to understand what is in your file. A conventional arrest warrant is issued after prosecutors have filed a criminal complaint, and the Sesslin standard controls whether the factual showing is good enough. A Ramey warrant, developed after the California Supreme Court’s 1976 decision in People v. Ramey, is a pre-complaint arrest warrant. It lets an officer get judicial authorization for an in-home arrest, based on a Declaration of Probable Cause, before the prosecutor has filed formal charges.8ALCODA. Ramey Warrants
The constitutional standard is the same for both: probable cause supported by a sworn factual showing. The difference is timing. A Ramey warrant issued under Section 817 does not start the formal complaint process under Penal Code Sections 740 or 813.3California Legislative Information. Penal Code Section 817 If your case involves a Ramey warrant rather than a complaint-based warrant, the Sesslin analysis still applies to the quality of the factual showing, but the procedural posture is different.