NEW YORK (CBSNewYork) – Investigators said the man accused of beating a tourist with a hammer in City Hall Park last month has admitted to the attack.

In court documents released during a hearing Tuesday, the man first identified as John Yoos said he “snapped” before launching the attack.

WCBS 880’s Alex Silverman reports

But the mystery about what triggered the attack is just one piece of the puzzle.

During Tuesday’s hearing, prosecutors said the suspect’s real name is Douglas Epp.

Authorities were notified that John Yoos may not be the suspect’s real name. The real John Yoos, a Canadian chess champion, told prosecutors he was alarmed this man was using his identity.

Yoos said he had met Epp years ago.

Epp pleaded not guilty to attempted murder. His defense lawyer told the court a psychiatric defense may be in the works.

The Spanish tourist suffered a spinal fracture and deep cuts in the attack, according to prosecutors.

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