Two police officers were fatally shot in the Des Moines, Iowa, area early Wednesday in what police officials say were “ambush-style” attacks. (The police later took a suspect into custody in connection with the shootings.) If those early reports prove correct, and if the officers were targeted by a shooter or shooters seeking to kill any police officers, then what was already the deadliest year in decades for terror attacks targeting police officers has gotten even deadlier. Attackers allegedly targeted police officers — any officers — in earlier deadly ambushes this year in Dallas; Baton Rouge, Louisiana; and Palm Springs, California.

As of July 20 — before the Palm Springs attack and the Urbandale, Iowa, shootings Wednesday — the nonprofit National Law Enforcement Officers Memorial Fund had counted 14 police officers killed in ambushes, compared with three during the same time period a year ago. And overall firearm deaths of police officers are up by about 50 percent from a year ago, according to counts through this week by both the memorial fund and another effort to track police-officer deaths, the Officer Down Memorial Page, which hasn’t yet tallied Wednesday’s Iowa attacks.

Republican presidential candidate Donald Trump repeatedly has cited the increasingly dangerous environment for police officers. “The attacks on our police, and the terrorism in our cities, threaten our very way of life,” Trump said in his speech accepting the nomination for president at the Republican convention. His Democratic opponent, Hillary Clinton, said at their first debate, “In a lot of places, our police are outgunned”; she also has called for improved police-community relations to increase public safety. (Clinton’s campaign on Wednesday canceled an event in Des Moines after the shooting occurred.)

Overall, the job of policing has gotten safer in recent decades. In 2016, the overall increase in on-duty deaths is 11 percent according to the memorial fund and 6 percent according to the memorial page; the number of officers dying of illness and heart attacks has declined. U.S. police officers killed by firearms account for a very small share of all gun deaths in the U.S. — far fewer than the number of people who fatally shot by police officers. And far more police officers are killed in terror attacks in other countries than in the U.S. We also don’t yet know the motive, if any, in the Iowa shooting. But it could be the latest attack in a year that already has been the deadliest since the 1970s for officers who were targeted simply because of the uniform they wear.