Dresden police and prosecutors said on Tuesday that they had arrested a 21-year-old Syrian who is connected to the Saturday night knife attack on a tram. He was arrested on Tuesday morning, police said, and is suspected of causing grievous bodily harm and other offenses. The suspect had been arrested previously and released shortly after the incident, as there was no indication that he was directly involved in the injury of the young American. But investigators say new information may link him more directly. Police said in a statement that after further investigation, there was a reasonable suspicion that he "had been involved in the knife attack on the 20-year-old American and had also injured the victim with a dangerous object." The statement on Tuesday did not make any direct reference to a second suspect who was initially thought to be the main perpetrator in the injuries to the American man. By Monday afternoon, East German Saxony authorities were still looking for him and appealed to potential witnesses for help. The US embassy in Berlin called for swift, harsh punishment The victim was injured after he intervened on behalf of another passenger who was being harassed on the tram, police said. The US embassy in Berlin condemned "the horrific attack" in an online statement and called on "the German authorities to bring the perpetrators to justice swiftly and punish them to the full extent of the law." The victim had facial wounds, but police said the injuries were not life-threatening. Police and prosecutors said their investigations were still ongoing, and as a result, they were still unable to provide additional details. Editing: Wesley Docher