A man suspected of killing three people and injuring eight others in a knife attack at a German festival told police “‘I am the one you are looking for” after he handed himself in.

German police took the 26-year-old man into custody on Saturday night. He is suspected of stabbing two men, aged 67 and 56, and woman, 56, in Solingen, western Germany. He is also suspected of injuring eight others.

The man reportedly walked into the police station covered in blood shortly after 11pm on Saturday. He told officers: “I am the one you are looking for”, according to German news outlet Bild. He reportedly hid in a back garden since after the mass stabbing on Friday night.

A 36-year-old man and a 15-year-old boy were also arrested in connection with the terror attack.

The teenager is not the main suspect but is alleged to have known about the attack. The man was arrested in a building for refugees close to the site of the attack.

Police in Germany said they have not ruled out a “terrorist motive” after the mass stabbing at a festival on Friday night. Police warned people to stay vigilant as well-wishers started to leave flowers at the scene. Authorities set up an online portal where witnesses can upload footage and other information relevant to the attack.

It comes after the Islamic State militant group claimed responsibility for the attack. The group said the attacker targeted Christians and is a “soldier of the Islamic State” and acted “to avenge Muslims in Palestine and everywhere”.

German interior minister Nancy Faeser visited the scene in Solingen on Saturday evening. She said that the government will support the city and the people of Solingen. She said: “We will not allow that such an awful attack divides our society.”