The suspect in the killings of two Israeli Embassy workers in Washington on Wednesday shouted “Free, free Palestine” as he was arrested, chanting the same slogan, in the same cadence, that has rung out in pro-Palestinian protests at college campuses and on American streets for years.

But the ties of Elias Rodriguez, the suspect, to the wider pro-Palestinian movement remain unclear. Was he a vigilante, upset at the deaths of civilians in Gaza, who decided on his own that violence was the only way forward? Or was he influenced by more extreme pro-Palestinian organizations that reach Americans online and that glorify the actions of Hamas and other armed resistance groups?

In either case, the killings of the Israeli embassy workers, Yaron Lischinsky, 30, who grew up in Israel and Germany, and Sarah Milgrim, 26, who was from Kansas, cast a harsh spotlight on the pro-Palestinian movement in the United States and the impact even peaceful protests might be having on attitudes against people connected to Israel.

The killings also risked painting all pro-Palestinian activists, the vast majority of whom do not engage in violence, with the same brush, which could lead to further repression of their movement. The tragedy occurred just as the movement has been trying to sustain attention in the United States on a blockade by Israel that has put Gaza residents at risk of widespread starvation.

Oren Segal, senior vice president of counter-extremism and intelligence at the Anti-Defamation League, said that while attending a rally or being a member of pro-Palestinian groups does not predict violence, the broader ecosystem being created, particularly online, by groups strongly opposed to Israel, “created an environment that made the tragedy last night more likely.”

“What people are hearing is a regular drumbeat: Israel is evil, supporters of Israel are evil, and we need to do anything by any means to fight back,” he said. “And many of them are conflating Jews with the policies of Israel, too.”