Marcus Carter and his friends sat directly behind the yellow barrier tape; behind them pylons were lined up in the green grass. Whenever a light-rail train passed, he raised his fist in the black power salute. Carter was wearing a T-shirt with "Black Lives Matter Dallas" written on it.

"We are sick of it," Carter said. "We've had enough of all the racism. If something doesn't change soon, there will be big trouble." Police officers stood by, making their presence known, ensuring that Carter and his friends wouldn't stumble onto the tracks when the streetcar approached.

In the past week, two black men were killed by police, first in Louisiana and then in Minnesota. Videos of their deaths at police hands triggered a national outcry. The activist group Black Lives Matter called for nationwide protests. On Thursday, people of all races and ethnicities united to march against police violence on the streets of Dallas. Suddenly, shots were fired and the masses dispersed.

Other than the fact that five officers had been shot dead overnight, it was not clear what had happened until Friday, when it turned out that a lone sniper had holed up in a building with the intent of shooting police. Officers claim that, just before they killed the man with a bomb delivered by a robot, he had said his intent was to kill white people, though he had specifically targeted police with his fire. It was later reported that the shooting suspect was an Army reservist who had been sent home from deployment in Afghanistan after he was accused of sexual harassment.

'A mutual path'

On Saturday, Officer Mike Walton stood in front of the Dallas police station and looked at a small square in front of the entrance. Two police cars parked there were covered with heaps of flowers and notes of appreciation and consolation. Red, white and blue balloons floated in the hot air; candles flickered on the ground. From across the region, people had come to pray, sing, cry or pay silent respects.

"Things will never be the same again," Walton said. "And we still have to go on and look for a mutual path." He has worked in Dallas for a quarter of a century. As a member of the Fraternal Order of Police, which advocates for law enforcement autonomy, he had worked to develop the department's de-escalation strategy. He said there were fewer clashes between civilians and police in Dallas than in other major US cities - a fact he is proud of. "We always made sure we worked in mixed teams," Walton said. "Violence between white policemen and blacks is a big problem."

In recent years, fresh attention has been drawn to police violence in the United States, but the events of the past week have little precedent in the country's modern history. "We should not allow ourselves to be guided by hate and anger," said Dorris Kenny, an African-American woman who has lived in the Dallas area for over 40 years. She said Dallas had appeared to be on the right path for handling the US's history of racial injustice.

Nonetheless, she was concerned about the consequences of last week's shootings - not just in Dallas, but in the rest of the country, as well. "There are still politicians who incite racial hatred," Kenny said. "That is dangerous, and we should not allow it." In the end, the upcoming elections will decide which route the United States will take in the future: "Do we want to work on making America a home for everyone? Or do we want to trigger a dangerous racial war?"

At a memorial, people put their hands together to pray. Young and old, black and white, they stood side by side in long lines or formed circles; black hands clasped white hands. In that moment of sorrow, skin color and social status were temporarily not in the foreground. Later in the evening, the hot summer air cooled after a thunderstorm. It felt like a short breather in a long summer in which the United States will decide what kind of future it wants.