He read out from a copy of the recent judgement by the apex court that said persons with criminal backgrounds serving prison terms or were in police custody shall not vote in any election.
Referring to the Ranchi High Court order the speaker said it had directed that Lakra be taken to the Assembly but it was up to him to decide whether he could participate in the voting or not.
Singh told the house that he had sought advice from advocate general MS Anwar, who said the Supreme Court judgement did not affect the MLA's right to cast vote and he was entitled to participate in the voting.
"I have left it on the conscience of the MLA," the Speaker said adding the matter was closed.
The Ranchi District and Sessions court had on May 13 convicted Lakra and three others for killing a youth, who was allegedly in love with Lakra's niece and the two had decided to marry, and awarded them life in prison.
Lakra yesterday obtained the permission from the High Court to attend the house on Thursday.