Former senior Aum Shinrikyo member Makoto Hirata has appealed the Tokyo District Court ruling that sentenced him to nine years in prison for his role in three of the doomsday cult's crimes in 1995, sources familiar with the matter said Monday.

Hirata, 48, filed his appeal last Thursday. The March 7 ruling that found him guilty in the abduction and fatal confinement of a Tokyo notary, as well as the bombing of a Tokyo condominium and the firebombing of an Aum facility, both of which were intended to impede police investigations.

Hirata's case was the first involving an Aum member to be tried under the lay judge system, which involves a panel of three professional and six lay judges.

Hirata maintained that he did not have prior knowledge of the abduction and bombings. The prosecutors called for a 12-year term but his lawyers sought four years. Some experts criticized the nine-year sentence that was ultimately handed down as too harsh.

Minoru Kariya, the 54-year-old son of Tokyo notary Kiyoshi Kariya, who died after being given an anesthetic drug by the cult, welcomed Hirata's appeal and said he hopes the Tokyo High Court will examine the case further.

Hirata turned himself in to police on Dec. 31, 2011, after nearly 17 years on the run.