Editor\u2019s Note: It is clear that several protesters threw objects at police, vandalized, and burned tires and flags. This story is not about them. SAN JUAN - A May Day protest in Puerto Rico turned violent as police officers in riot gear clashed against civilians carrying wooden shields in the archipelago\u2019s Milla de Oro or Gold Mile, where the central offices of major banks and investment firms are located. The secretary of the Department of Public Safety, H\u00e9ctor Pesquera, said on a local radio station that the Puerto Rico Police Bureau (PRPB) wanted to stop the demonstrators from reaching the offices of the Financial Oversight and Management Board for Puerto Rico. Videos from TV stations and others posted online show some protesters dressed in black and with their faces covered pushing through a line of police officers in riot gear. As the police line seemed to be breaking, police pushed back and shot tear gas canisters. In one video, 18 shots of tear gas canisters seem to be heard as people ran away coughing and in panic. About 12 of those shots were heard after protesters were already retreating. Thread Video sent to me by security guard Daniel Pe\u00f1a shows the moment police used tear gas on protesters in Puerto Rico. Riot police were holding the line when a small group of protesters advanced on them; cops pushed back, objects were thrown at police who then deployed gas pic.twitter.com\/DaEN1YpjMx \u2014 David Begnaud (@DavidBegnaud) May 2, 2018 The protest ended with 19 arrests, and hundreds of civilians injured or affected by tear gas. The Police reported 15 injured officers. The May Day protest was organized to not only celebrate the International Workers\u2019 Day, but also to demonstrate against the austerity measures proposed by the Oversight Board and the Commonwealth of Puerto Rico. These measures include closing almost 300 schools and transitioning many of the remaining ones to charter schools, significant tuition hikes in the University of Puerto Rico and the slashing of pension benefits. The American Civil Liberties Union (ACLU) in Puerto Rico sent legal observers to the May Day protest and reported that the police used tear gas and other tactics to break up the protest, not to safely manage the crowd. \u201cThe government\u2019s motive, more that guaranteeing the right of the protesters to express without worry and maintaining a safe environment, was to suppress the expression,\u201d said Josu\u00e9 Gonz\u00e1lez Ortiz, an ACLU staff attorney, in a press conference. \u201cThe government made itself enemy of the expression, and its mobilization was exaggerated.\u201d \u201cSince the beginning, they blocked the public streets, that are the scene of protected expression, precisely to hinder expression, and that causes tension among the protesters,\u201d he added. Amnesty International has also spoken out against police response to the protest. PRPB\u2019s press office decline to comment specifically about the May 1 incidents and the apparent disproportionate use of tear gas. Latino Rebels was directed to contact lieutenant colonel Juan C\u00e1ceres M\u00e9ndez because he was in charge of the operation. In a phone call, C\u00e1ceres also declined to explain why did the police keep shooting tear gas as demonstrators were retreating. He directed Latino Rebels to contact SWAT because it is the division in charge of deploying tear gas. At the time of publishing, PRPB\u2019s press office had not provided the contact information of the SWAT\u2019s director. On July 2008, the U.S. Department of Justice started an investigation into civil right violations by the Puerto Rico Police Bureau. In 2011, the the DOJ concluded, among other things, that the PRPB showed patterns and practices of excessive force in violation of the Fourth Amendment of the U.S. Constitution and patterns of unreasonable or improper conduct to limit freedom of expression protected by the First Amendment. The DOJ\u2019s report also said that the PRPB engaged in a pattern of unlawful searches and seizures in violation of the Fourth Amendment. On July 2013, the Government of Puerto Rico, the police and the DOJ signed an agreement that prompted a police reform. Among the agreed terms, the police would have to develop a crowd control policy and techniques that respect freedom of expression and the right to lawful assembly. These policies include warning civilians to disperse and notifying them of the available exit routes before using crowd management tools such as tear gas. They also direct police to \u00a0decrease the level of force used as the protesters\u2019 resistance declines. Gonz\u00e1lez said that at no point did PRPB or any of its units warn demonstrators about the imminent use of force. \u201cThere was no interest in dispersing because there was nowhere to go,\u201d Gonz\u00e1lez said. \u201cThey were cornered.\u201d The new policy for crowd control has been in effect since 2016, but in February 2018 no officer had received training for it, according to Noticel. Police officers were expected to complete said training by July 2018. \u201cThe police is administering that and other trainings as part of the agreements,\u201d said Axel Valencia, PRPB\u2019s press director. \u201cThe police is supposed to have finished these trainings.\u201d At the time of publishing, PRPB\u2019s press office did not confirm that these trainings were in fact completed. A December 2017 report filed in court by the Technical Compliance Advisor (TCA) of the federal court case, Arnaldo Claudio, said that the Police Department lacked transparency. \u201cIn this six-month report, it is appropriate to discuss PRPB\u2019s (Puerto Rico Police Bureau) lack of cooperation with the TCA and the PRPB\u2019s failure to comply with the TCA requests for documents and information,\u201d the report said. Another recent report filed by the TCA said that the Puerto Rico Police had a "leadership crisis" due, in part, to the creation of the new Department of Public Security, headed by H\u00e9ctor Pesquera. It also presented concerns in regards to PRPB\u2019s lack of an integrated work plan with the role of each specialized unit to avoid duplication and misunderstandings in the execution of functions, according to El Nuevo D\u00eda. The apparent excessive use of tear gas was not the only incident where police officers demonstrated questionable behavior. As police followed protesters for several miles into a residential area in R\u00edo Piedras,\u00a0known for student housing, a police officer hit a journalist in the ribs\u00a0with his baton. Another officer was recorded in a separate incident, daring a protester to cross the police line, calling him a pendejo and a \u201ccock sucker.\u201d pic.twitter.com\/vw5m1O08fk \u2014 Perla Rodr\u00edguez (@perladelm) May 1, 2018 Following suit, a group of police officers took selfies after entering a private property without a warrant and arresting at least one suspect. Police said that it happened during a hot pursuit, giving officers legal authority to follow the suspect inside. Another group of officers took a selfie with one of the wooden shields carried by protesters, perhaps as a sign of victory, and a man selling bottled water was supposedly shot with rubber bullets. In an informative session before the May Day clashes, governor Ricardo Rossell\u00f3 told journalists that DPS secretary Pesquera, the police commissioner and himself had learned their lesson from the May Day protest of 2017, according to El Vocero. On that occasion, mayhem ensued in Milla de Oro as police seemed unable to control the crowds. On May 4, federal judge Gustavo A. Gelp\u00ed designated Technical Compliance Advisor investigator Jos\u00e9 Pujol \u201cto conduct an independent evaluation and assessment, followed by a report, of the May 1 demonstrations,\u201d according to ACLU Puerto Rico. This is a big deal. Federal judge issues order for US to conduct an independent review of #PRPD response to #MillaDeOro protest on May 1 in #PuertoRico. Wonder what @ricardorossello is thinking now? pic.twitter.com\/V70F9iGrNE \u2014 Julio Ricardo Varela (@julito77) May 4, 2018 \u201cThe parties shall fully cooperate with him,\u201d wrote Gelp\u00ed. The executive director of ACLU, William Ramirez Hern\u00e1ndez, warned the day before that the police will needlessly continue escalating protests unless PRPB takes immediate action. \u201cThis has to be corrected as soon as possible, Ram\u00edrez said in a press conference. \u201cIt is going to end very bad.\u201d *** Omar Rodr\u00edguez Ortiz is a graduate student at The School of Journalism at The University of Texas at Austin. He has written for Texas Monthly, The Austin Chronicle, UT's Knight Center, Di\u00e1logo PR and other outlets He tweets from @ORO_PUR.