(Bloomberg) -- Puerto Rico Governor Pedro Pierluisi on Tuesday ordered flags flown at half-staff and declared three days of mourning after three police officers were killed, the latest round of shocking violence to plague the U.S. commonwealth.

On Tuesday, police said the investigation was ongoing, even after they recovered a bullet-riddled body of a man with a sign on his neck reading, “I was responsible for the killing of the guards. Here he is.”

The homicide rate in Puerto Rico is about four times the U.S. national rate. Although it has been dropping, the dramatic nature of the violence can make it all-the-more terrifying. The island is in a long population slump, and some out-migrants cite safety concerns for leaving.

The three officers, state policeman Luis Marrero Diaz, and municipal police, Luis Salaman Conde and Eliezer Hernandez Cartagena, were shot Monday afternoon as they chased a group of men in a stolen car near the island’s capital. All three died from their wounds.

The empty automobile involved in the chase was later found at the Luis Llorens Torres apartment complex in San Juan’s Santurce neighborhood.

The incident is one of the first major challenges for Pierluisi, who took office Jan. 2. On Tuesday, he said the case would remain under investigation until all the suspects had been caught.

“There’s no room for these violent acts and this disdain for life in the Puerto Rico that we want,” he said in a statement.

Puerto Rico recorded 346 murders during the first seven months of 2020, according to the most recent police data. An analysis by local media found that 2020 ended with 529 homicides -- the lowest number in three decades.

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