LOS ANGELES -- A spate of incidents in which Los Angeles police officers are under investigation for use of excessive force is threatening to erode the Police Department's hard-won efforts over several years to bolster community relations.

Video in recent weeks has captured officers punching a handcuffed suspect and slamming a restrained woman to the ground. In the third case, a woman stopped breathing in the back of a police car and later died.

The incidents come after years of reforms by the LAPD to improve its officers' conduct.

The efforts, undertaken under a federal court order, have yielded results: The city's crime rate is the lowest in four decades, and police are getting praise from communities, including minorities and gays, that had historically complained about mistreatment.

The recent incidents remain in the early investigative stages and none of the officers involved have been charged.

But they underscore that for some police officers on the street, the line on acceptable use of force remains blurry.

"There's been a real effort to change the culture," said Joe Domanick, a professor at the John Jay College of Criminal Justice who is writing a book on the transformation of the LAPD after the Rodney King beating. "It takes a long time for a culture to change, for things to trickle down."

Andrea Ordin, president of the Los Angeles Police Commission, the department's civilian oversight panel, said it's too early to tell if a trend toward overaggressive tactics is developing.

"We are seeing community groups coming to our meetings and talking about the changes in the Police Department and that they appreciate the better communication," she said. "At the same time, we're seeing these incidents. Each of these has to be investigated thoroughly."

In one incident, Alesia Thomas died in a squad car July 22 after struggling with officers trying to arrest her on suspicion of child endangerment. She had left her two children at the police station where they told officers their mother didn't want them, and they had not eaten for several days, said Cmdr. Andrew Smith.

During the struggle to get Thomas into the patrol car, a female officer was captured by the car's video camera threatening to kick Thomas in the groin if she did not obey, and then she made good on the threat. A short while later, Thomas stopped breathing. The coroner has not determined what caused her death.

Police Chief Charlie Beck has reassigned the five officers involved and ordered an investigation.

On Aug. 21, registered nurse Michelle Jordan was pulled over for holding her cellphone while driving. She got out of the car and did not comply with an officer's demand to get back in the vehicle. The 5-foot-4-inch woman was slammed to the ground and handcuffed by at least one officer. While being led to the patrol car, an officer slammed her to the ground again.

The incident was captured by a surveillance camera at a nearby restaurant.

The officers involved were removed from patrol duty pending an investigation, and their supervising captain was transferred. Beck said the videotape raised serious concerns and ordered it shown at officer roll calls throughout the department.

In a third incident, college student Ronald Weekley Jr. was stopped Aug. 18 by officers for riding his skateboard on the wrong side of the street. A bystander's cellphone video appears to show that an officer punched the 20-year-old in the face while he was on the ground being handcuffed with four officers on top of him. He said he suffered a broken nose and cheekbone.

Weekley was arrested on suspicion of resisting arrest. Police have launched an internal investigation to determine whether excessive force was used, but the officers involved remain on duty.

"These are unarmed, handcuffed suspects. It's a disturbing, growing trend of police brutality throughout Southern California," said Najee Ali, of the South Los Angeles civil rights group Project Islamic Hope. He noted two other nearby cases that outraged citizens: The police killing of two suspects last month in Anaheim, which sparked a riot, and the July 2011 fatal beating of a handcuffed, homeless, mentally ill man in Fullerton.

Smith, the LAPD commander, said use-of-force incidents are not on the rise. The department records about 1,600 such cases annually, a number that has remained constant in recent years.

"That's out of the millions of contacts we have with the public and the tens of thousands of arrests. Because there's videotape in these incidents, they get a lot of media attention," Smith said.

Los Angeles Police Protective League Tyler Izen urged the public and the department not to judge the involved police officers before all the evidence is heard.

"Police officers perform a tough and dangerous job every day," Izen said in a statement. "Officers often need to make split-second, life-or-death decisions. Like everyone in this great country, they deserve the benefit of the doubt."

Officers are permitted to use "reasonable" force to make an arrest, prevent a suspect's escape and overcome resistance. "The question is, is it objectively reasonable? If it isn't reasonable, we hold them accountable," Smith said.

Officers are also extensively trained to verbally persuade people to do what they want without resorting to force, said Richard Weinblatt, a former police chief and police consultant who is a dean at Ivy Tech Community College in Indiana.

Police academy trainers, however, notice that younger cadets, who grew up communicating via text messages and email, and in an era where schoolyard fights are not tolerated as they once were, often lack verbal communication skills and experience in dealing with physical aggression, Weinblatt said. At the same time, criminals are more violent than ever.

"Officers are just plain scared," Weinblatt said. "They don't have the communication skills or physical confidence of previous generations. They're jumping higher and quicker on use of force because of that fear element."

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Browse Los Angeles sousveillance videos from 1992 to the present to see the big role individuals have played in reforming powerful institutions.
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  • Rodney King

    In this 1991 video, <a href="http://www.cnn.com/2012/04/28/us/rodney-king-profile/" target="_hplink">Rodney King is beaten</a> by a group of police officers. It is known as one of the most infamous police brutality cases, and the acquittal of the officers involved, one year later, sparked the <a href="http://www.huffingtonpost.com/news/la-riots/" target="_hplink">Los Angeles riots</a>.

  • William Cardenas

    In this 2006 video,<a href="http://www.washingtonpost.com/wp-dyn/content/article/2006/11/10/AR2006111001666.html" target="_hplink"> William Cardenas is seen being beaten by two LAPD officers</a>. Cardenas was reportedly resisting arrest after being seen drinking a beer on the sidewalk. The use of excessive force was deemed appropriate, but led to national news coverage of Copwatch initiatives.

  • May Day Melee

    This 2007 video was filmed at a May Day rally in MacArthur Park where undocumented immigrants were rallying for amnesty. Approximately 600 LAPD, both in helicopters and on the ground, began to descend on the area after declaring the event an unlawful assembly.

  • May Day Melee

    In response to the excessive force used by the LAPD at the May Day Melee, Mayor Antonio Villaraigosa personally oversaw the investigation and Police Chief William Bratton announced an attempt at reorganizing the LAPD. The city was ordered to pay <a href="http://articles.latimes.com/2009/feb/05/local/me-lapd-settlement5" target="_hplink">$12.85 million in a class action lawsuit</a> to the people who were hurt.

  • City Bus Abuse

    From the <a href="http://www.youtube.com/watch?v=vsW23kbVLs0" target="_hplink">UnivisionNews1</a> channel on YouTube: <blockquote>A cell phone camera caught the moment when an LAPD officer struck a mentally ill woman aboard a city bus. They were called in after she displayed erratic behavior. Civil rights activists argue he used excessive force and demand an investigation.</blockquote>

  • Hollywood Blvd Counter-Protest

    In this 2008 video, counter-protesters along the sidewalks gathered on Hollywood Boulevard as the Minuteman civilian border patrol group marched in the streets. When counter-protesters tried to join in the march, police stopped them because they did not have a permit, while the Minutemen did. ABC Los Angeles notes that sometimes, <a href="http://abclocal.go.com/kabc/story?section=news/local&id=4349432" target="_hplink">the police used force</a> to keep counter-protesters from the street.

  • Diop Kamau

    In this video from <a href="http://policeabuse.com/" target="_hplink">PoliceAbuse.com</a>, we learn about Diop Kamau (also know as Don Jackson), a former Police Sergeant Detective with the Hawthorne Police Department who went undercover to expose racism and violence in his own police department. Kamau went on to become the founder and executive director of the Police Complaint Center and the CEO of PoliceAbuse.com. Kamau has made it his mission to identify, investigate and reform police misconduct.

  • Donovan Jackson

    In this 2002 video by Mitchell Crooks, officers from both the LA County Sheriff's Department and the Inglewood Police Department are seen using excessive force against Donovan Jackson, a 16-year-old who suffers from a developmental disability. Jackson's father's car was unregistered, which is why the police stopped them. The video begins with Donovan face down, handcuffed on the asphalt. Moments later he is unconscious due to the way the officers were pulling on the chain he was wearing. This case had major reverberations throughout Inglewood. Following the trial of the police officers, two white police officers filed a discrimination suit against the city for being treated more harshly than their black counterparts. <a href="http://articles.latimes.com/2005/mar/08/local/me-donovan8" target="_hplink">They won $2.4 million</a>. <a href="http://query.nytimes.com/gst/fullpage.html?res=9C04E3DC163CF93AA35750C0A9639C8B63&ref=donovanjackson" target="_hplink">Donovan's family eventually settled</a> with the City of Inglewood for an undisclosed sum. The City of Inglewood and LA County never admitted any wrongdoing or liability.

  • Kelly Thomas

    In this 2011 video,<a href="http://www.huffingtonpost.com/2011/09/21/kelly-thomas-death-police-charged_n_974237.html" target="_hplink"> Kelly Thomas is seen beaten to death</a> by members of the Fullerton Police Department who were responding to the scene after someone called in a robbery. Officer Ramos can be heard saying, <a href="http://documents.latimes.com/charges-kelly-thomas-police/" target="_hplink">"Now see my fists? They are getting ready to fuck you up,"</a> to Thomas before beating him. <a href="http://www.huffingtonpost.com/2011/09/21/kelly-thomas-death-police-charged_n_974237.html" target="_hplink">Ramos was later charged with murder</a>. Cpl. Jay Cicinelli faces manslaughter charges. A trial is pending.