Lawyers can still use the testimony of retired SPO3 Arthur Lascañas regarding the existence of the Davao Death Squad (DDS) in a court of law, even if he lied under oath during a congressional hearing.

The real test of whether Lascañas was telling the truth when he confessed to the existence of the DDS will come not in the chambers of Congress, but in a courtroom, a legal expert said.

• READ: UN urged to investigate Davao Death Squad allegations

"Kapag may sampa na iyong kaso at siya ay gawin na testigo, then we can test through cross-examination kung kapanipaniwala nga ang kanyang mga sinalaysay," said Fr. Ranhilio Aquino, dean of the San Beda Graduate School of Law.

(If a case is filed and he is made a witness, then we can test through cross-examination if he was telling the truth.)

Currently, there is no legal issue, Aquino said, because Lascañas was not under oath when he affirmed on Monday the existence of the DDS, in contrast to his statement last year that it was only "media hype."

"The moment that he puts that under oath, then he will face the issue of whether or not he has perjured himself," Aquino said.

Lascañas will be accused of perjury if it can be proved that he knowingly made a false statement, and there are no reasons for his act to be excused.

"In other words, kahit na he knowingly made a false statement, kapag may excusing circumstance na he was under threat, or he was intimidated, that excuses him from the criminal act of perjury,"Aquino said.

(In other words, even if he knowingly made a false statement, if there are excusing circumstances such as he was under threat, or he was intimidated, that excuses him from the criminal act of perjury.)

However, he cautioned against dismissing either of Lascañas' stories, because the truth has yet to be established.

While "it is possible, as a matter of theory" to believe Lascañas' 2nd statement more, because he had more time to think about what he did, the truth of his statements can only be established during cross-examination.

Currently, Duterte enjoys presidential immunity, but Aquino said that his alleged accomplices can be charged in the meantime.

"Your inability to charge Duterte now does not cover other officials. The non-impeachable officials can be prosecuted," he said.

Senators have urged an investigation of Lascañas' claims that he killed people on orders of then-Davao City Mayor and now-President Rodrigo Duterte.

Last year, he dismissed allegations of self-confessed hitman Edgard Matobato regarding supposed vigilante missions, which he retracted in a press conference yesterday.

• READ: Lascañas list: Alleged sins of the Davao Death Squad