BANGKOK, June 19 (Xinhua) -- A male murderer has been executed by lethal injection in central Thailand, the first execution in nine years.

Theerasak Longji, 26, was ruled brutal murder and crime of robbery by the Appeal Court and the Supreme Court. He was then handed down the death sentence.

He stabbed a victim 24 times to rob his mobile phone and a wallet in 2012, according to the Department of Correction on Monday.

The execution, on Monday, lasted for three hours, reports said.

Ministry of Justice issued a regulation on execution by lethal injection in 2003, replacing execution by firing squad, according to the department.

The department said Theerasak was the seventh executed by lethal injection since the method was introduced.

Thailand sees a total of 325 convicts executed since 1935, among which 319 were executed by firing squad, according to the department.