Tokyo, May 22 : A man suspected of throwing an explosive device towards Japanese Prime Minister Fumio Kishida last month will undergo a psychiatric evaluation, informed sources said on Monday. The Wakayama Summary Court in western Japan has approved the request from prosecutors to keep the alleged assailant, 24-year-old Ryuji Kimura, for psychiatric evaluation, until September 1, reports Xinhua news agency. Specifically, the prosecutors in the case wish to determine through the psychiatric evaluation whether Kimura can be held criminally responsible for his involvement in the alleged attack. Kimura, from Hyogo prefecture, is alleged to have thrown the explosive device towards Kishida as the latter was about to make a stump speech at a local fishing port in the city of Wakayama on April 15. Kishida was not hurt in the attack, but a police officer and another person sustained minor injuries as a result of the attack, according to local media. Kimura was swiftly arrested at the scene on suspicion of obstructing business and was later served a fresh arrest warrant for manufacturing explosives in violation of Japan's firearms control law. According to investigators, Kimura has remained silent since his arrest, but they are trying to determine if he held a grudge against Japan's election system as he had sued the government in June last year, claiming he was unable to run in the upper house election last year due to some restrictions, including age. The latest attack comes less than a year after former Prime Minister Shinzo Abe was fatally shot by an assailant with a homemade gun while making a stump speech. /IANS