Isayeva v. Sacramento Sheriff's Department, 2017 U.S. App. LEXIS 19018

On Feb 18, 2013, Deputies Sean Barry and Corbin Gray responded to domestic-disturbance calls about Paul Tereschenko, who exhibited possible mental illness and methamphetamine use and had yelled about voices and killing a family member.
Tereschenko (6'+, >250 lbs) was unarmed; after 7–10 minutes of interaction he became agitated, said “you’re gonna have to shoot or kill me,” and resisted when deputies attempted to detain him under Cal. Welf. & Inst. Code § 5150.
A brief physical struggle ensued; deputies attempted control holds, Tereschenko resisted and shoved the officers, and Deputy Barry deployed a taser in drive‑stun mode for one five‑second cycle.
The tasing provoked an escalated brawl: Tereschenko allegedly struck both deputies, shoved Barry into a wall/bed, and pummelled Barry until Barry began to lose consciousness; Gray attempted a carotid/choke hold but failed to restrain Tereschenko.
While officers were grappling, Deputy Barry yelled (or at least called out) “Shoot him”; Barry then fired three shots, killing Tereschenko. Isayeva (the decedent’s wife) sued under 42 U.S.C. § 1983 alleging excessive force; district court denied Barry qualified immunity at summary judgment.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Appellate jurisdiction to hear interlocutory appeal of denied qualified immunity	Denial of summary judgment was reviewable because claim raises qualified immunity	Denial was interlocutory; appellate review limited but allowed to consider legal questions about qualified immunity	Court has jurisdiction to decide qualified immunity questions when facts construed for plaintiff and legal prong (clearly established law) is at issue
Use of taser (drive‑stun)	Isayeva: tasing was excessive and unconstitutional (no adequate warning; mental illness; nonviolent/unarmed)	Barry: tasing was reasonable given active resistance, size disparity, suspected drug use, and immediate threat to officers	Barry entitled to qualified immunity for the tasing—existing Ninth Circuit and Supreme Court precedent did not clearly establish that tasing here was unconstitutional
Use of deadly force (shooting)	Isayeva: Garner prohibits deadly force absent probable cause that suspect poses significant threat of death/serious injury; no such threat existed here	Barry: he was being beaten, losing consciousness, at risk of being disarmed or killed; circumstances justified belief of imminent serious harm	Barry entitled to qualified immunity for the shooting—circumstances (size disparity, successful resistance, injuries to deputy, drug influence, threat of incapacitation) did not render unlawfulness "beyond debate"

Graham v. Connor, 490 U.S. 386 (1989) (Fourth Amendment excessive‑force reasonableness standard)
Tennessee v. Garner, 471 U.S. 1 (1985) (deadly force permissible only if officer has probable cause to believe suspect poses significant threat of death or serious physical injury)
Pearson v. Callahan, 555 U.S. 223 (2009) (qualified immunity prong sequencing and framework)
Ashcroft v. al‑Kidd, 563 U.S. 731 (2011) (existing precedent must place question beyond debate to deny qualified immunity)
Mullenix v. Luna, 136 S. Ct. 305 (2015) (qualified immunity protects all but plainly incompetent or knowing violators)
Brosseau v. Haugen, 543 U.S. 194 (2004) (use of general standards may not clearly establish law absent analogous facts or an "obvious case")
White v. Pauly, 137 S. Ct. 548 (2017) (requires close factual analogy to clearly establish right)
Mattos v. Agarano, 661 F.3d 433 (9th Cir. en banc 2011) (taser precedents and excessive‑force analysis)
Bryan v. MacPherson, 630 F.3d 805 (9th Cir. 2010) (dart‑mode tasing held unconstitutional under facts)
Hughes v. Kisela, 862 F.3d 775 (9th Cir. 2017) (example of an "obvious case" where deadly force was not protected by qualified immunity)
Deorle v. Rutherford, 272 F.3d 1272 (9th Cir. 2001) (consideration of suspect’s mental state in force analysis)
Hopkins v. Andaya, 958 F.2d 881 (9th Cir. 1992) (hand‑to‑hand combat case where shooting was excessive under those facts)