Police on Saturday served fresh arrest warrants to a 47-year-old man suspected of attempted murder in a knife attack on three elementary school boys in Nerima Ward, Tokyo.

The man was arrested Friday in connection with the attack earlier that day but has chosen to remain silent, investigators said. The police also raided the man's house Saturday to search for a motive for the attacks.

The unemployed man allegedly attacked the boys, two aged 6 and one 7, on a street near Oizumi Daiichi Elementary School. After scuffling with a 71-year-old crossing guard who was attempting to protect the children, the man fled in a car, police and witnesses said.

The police located the vehicle in Miyoshi, Saitama Prefecture, and arrested the man, who was found inside armed with a fruit knife. They suspect the man targeted the children because footage from a surveillance camera showed that his car was parked in front of the school's main gate around 20 minutes before the incident.

Since some of the man's depositions do not make sense, the police are also investigating whether he is mentally fit enough to be held responsible for the crime and are refusing to disclose his identity.

The 7-year-old victim suffered deep arm cuts while the other two children sustained cuts to the neck. Their injuries are not life-threatening, the police said.