Diego Alfonso Rios Died After Claremont Use-of-Force Incident

Family of Diego Alfonso Rios Seeks Answers After His Death Following Police Stop in Claremont

CLAREMONT, CALIFORNIA (December 1, 2025) – A Rancho Cucamonga man identified as Diego Alfonso Rios has tragically died after a Claremont police stop near Claremont Boulevard and Andrew Drive.

Los Angeles County officials are saying that the incident took place around 3:18 p.m. on Friday. The police received reports that a man later identified as Diego Rios was acting erratically and may be under the influence.

Officers arrived at the scene and learned that the subject drove away. They were later able to locate him and initiate a traffic stop.

Diego Rios stepped out of his vehicle, and a use-of-force incident occurred. It remains unclear what led up to the use of force.

At some point during the encounter, he became unresponsive. Paramedics were called to the scene to help the victim. He was transported to the Pomona Valley Hospital Medical Center, where he was pronounced dead.

Family members said that they are seeking a second private autopsy and considering legal action. A full investigation remains ongoing at this time.

Liability for Los Angeles County In-Custody Deaths

Police officers have a legal obligation to use the least amount of force necessary for any given encounter. A police department can be liable for the excessive force of their officers. According to 42 U.S. Code § 1983, every person who, under the color of law, deprives someone of their rights afforded under the Constitution, shall be liable to the injured party in an action at law. There are many different ways that police officers could act negligently and contribute to the death of a person.

• Delayed Assistance: Police officers may delay getting a person adequate medical help as they are in the midst of a physical or mental health crisis.
• Illegal Restraints: Police officers may have restricted the breathing of a person by placing them in an illegal chokehold or prone position.
• Use-of-Force: Police officers may have used unnecessary force on a suspect. This may include punching, hitting, or repeatedly tasing a suspect. 

Many fatal police encounters involve officers that fail to follow police protocol for dealing with suspects who are in a mental health crisis or under the influence. Consider, for example, A.B. v. County of San Diego, No. D084376, Cal. Ct. App., 4th Dist. Deputies encountered a man in the midst of a mental health crisis. After a brief struggle, he was placed face down in a prone position. Within minutes he became unresponsive and was later pronounced dead. A Court of Appeal held that the facts of the case could support liability for the family’s wrongful death claim. 

Steps to Take After Los Angeles County In-Custody Deaths

Far too many people are seriously injured or killed every year during encounters with law enforcement in California. According to the Public Policy Institute of California, “About 195 people die each year from interactions with California law enforcement. Gunshots are by far the most common cause of death: nearly 250 people are shot by police each year.” It is important that individuals and families affected by police brutality take certain measures to protect the rights.

• Medical Records: All of the medical records related to the incident should be collected and reviewed. This will include an autopsy report.
• Body Camera Footage: Police officers in California must wear body cameras. The footage captured by these devices can be enormously helpful in determining if officers acted negligently.
• Investigation: All of the agencies that were involved in the arrest should be identified. This may include city police, county sheriffs, and private medical contractors.
• Legal Review: The family of any person who died in police custody should carefully consider all of their legal options with an experienced civil rights attorney.

Many in-custody deaths involving police officers are preventable. They may stem from situations where officers were either unwilling or unable to de-escalate encounters. Another major problem is that officers may not follow protocols for dealing with subjects who are potentially under the influence or in the midst of a serious mental health crisis. To make matters worse, police departments will virtually never accept responsibility if their officers injure or kill someone. A civil rights attorney can help identify all of the ways that officers may have broken protocol and contributed to a death.

Investigating Los Angeles County In-Custody Deaths

We at the Carrillo Law Firm extend our deepest condolences to the family of Diego Alfonso Rios. Any person who may have more information about what happened should reach out to investigators. There needs to be a thorough investigation into what went wrong.

Do you need more information about a Los Angeles County in-custody death? Our team of civil rights attorneys is here to answer any questions that you may have. We are committed to helping victims get the support and justice that they are entitled to under the law. Whether you just have legal questions or need a free, independent investigation into the unique circumstances of any incident, we are here to help. You can contact our office anytime at 626-799-9375.