"Given that these incidents cannot be looked at in isolation, the Mexican government has called for the U.S. Department of Justice through its civil rights division to monitor the investigation of these three cases to assure that they're conducted with transparency and where appropriate, the proper criminal or civil responsibility is determined," Mexico's Foreign Ministry said on Monday.
"Adding to our consternation over the third case of a Mexican killed by an excessive use of force in less than one month, is our deep concern for the effect of the break in trust between the Hispanic community and the police forces that could result from these actions," the foreign ministry said.
Investigators said they're still piecing together information on all three cases. No charges have been filed. Here's a look at what we know so far:
What will dash cam video show?
Protesters at a city council meeting in Grapevine, Texas, this week chanted a familiar refrain: "Hands up! Don't shoot!"
Police shot 31-year-old Rubén García Villalpando
in the Dallas suburb of Euless, Texas, on February 20.
Investigators say the case started when a burglar alarm sounded at a business. Villalpando's car, which was in the area, was followed by police in what authorities described as a high-speed chase. Eventually, Villalpando pulled over.
Villalpando was unarmed, but in early reports about the shooting, police said an altercation erupted after he disobeyed an officer's commands during a traffic stop.
The traffic stop was caught on camera, but police haven't released the dash cam video to the public.
"There will be more information released as the investigation continues. This additional information may shed more light on Mr. Villalpando's actions that night," police and city officials said. "We look forward to the time that the community can review the dash cam video of this incident, which we believe will answer many questions and correct some misconceptions about this incident."
Villalpando's family said they've seen the video, and even though it doesn't show the officer or the shooting, they said one thing is clear: Villalpando was unarmed and did nothing to threaten the officer who stopped him.
Fernando Romero said it was jarring to hear what his brother-in-law said in the video as he gets out of the vehicle.
"My brother-in-law is out of the car with his hands up," Romero said, "and the first thing he asks is, 'Are you going to kill me?'"
Marta Romero, Villalpando's wife, said her husband made a mistake when he didn't stop when the officer tried to pull him over. But she said he was trying to cooperate and turn himself in.
"He was painted like a criminal who was involved in a robbery and had assaulted an officer, and in the video you don't see any of those things," she said. "You see the opposite, a man who is scared, who is simply trying to calm the situation, who sees that the police officer has a weapon in his hands."
Sister: 'He did not deserve to die this way'
Police say Ernesto Javier Canepa Díaz, 28, was killed February 27 after a shooting broke out during a robbery investigation.
"At this time we need the process to continue in order to know what happened," Santa Ana, California, Police Chief Carlos Rojas told CNN en Español.
He declined to comment on the investigation, but said Canepa had been arrested in the past for various crimes, including narcotics possession, possessing stolen property, domestic violence and resisting police. When police came across his car last week, he was wanted for a series of robberies, Rojas said.
"He did not cooperate with the police and we know that a police officer shot various times at him and he died at the scene," Rojas said.
And police, he said, found a replica of a gun inside the car.
"We do not know if this is the reason why the police officer used force. That will be investigated," Rojas said.
Canepa's family said they don't believe police were justified in opening fire.
"Whatever it was, he did not deserve to die this way," said Mayte Canepa, Ernesto's sister. "He did not deserve for them to shoot at him like they did."
The Orange County Register reported
that at a press conference on Tuesday, Canepa's brother, Andres, described police as "a gang with a badge."
The officer who shot Canepa has been suspended with pay until the investigation is finished, police said.
Bystanders' videos capture shooting, but questions remain
A proud laborer from Mexico, Antonio Zambrano-Montes picked fruit in the orchards of Washington state, but when his most valuable tools -- his hands -- became injured last year, he fell into deep despair.
He couldn't work or send money to family in Mexico, two routines that shaped his life.
It was this misfortune that distressed Zambrano-Montes in the days before he and police in Pasco, Washington, clashed in February, in a confrontation that ended with officers firing 17 bullets, hitting Zambrano-Montes several times and killing him. He was unarmed but was accused of pelting police with rocks.
Police have said that Zambrano-Montes, 35, was throwing rocks at cars and trucks when confronted by officers. He then allegedly stoned two officers, and police resorted to deadly force, authorities said. Officers had used a Taser on him, but it wasn't effective, police said.
The shooting now haunts his family
, due in no small measure to how the hail of police bullets was captured on videos and posted on YouTube by bystanders. Zambrano-Montes' family said his limited English left him unable to understand the officers' commands, shouted in English.
His mother, Agapita Montes, said she didn't see her son throwing rocks in the videos.
"The only thing I can see is that he's running, he raises his hands and they still shoot him. Why? I ask myself. Why?" Montes said.
Erlinda Zambrano, an aunt of Zambrano-Montes, also found it very difficult to accept the police version of events, she said.
"We are living with profound pain from how he died, and it's something very bad and terrible," the aunt said. "I look at the videos now and I cannot sleep because it's too hard."