CHRISTCHURCH, New Zealand — The suspected gunman in last week’s attack on two mosques in Christchurch, New Zealand, was charged with murder for the death of one victim — but the police announced on Thursday that that supposed victim was in fact alive.

A police spokesman said that the charge sheet would be corrected, with a new name, and legal experts said the mistake would not impede prosecution in the mass shooting that left 50 people dead.

“In our system there is a provision to amend the charge at any time, and the issue is whether the amendment is in the interest of justice,” said Jonathan Eaton, a lawyer and former prosecutor specializing in criminal law. “I will imagine there will be a fairly hasty effort to amend that charging document.”